[patch 06/10] Move lockdep to instrumentation

[Mathieu Desnoyers]

Move lockdep.c, lockdep_internals.h and lock_proc.c to instrumentation/.

Should we move the lockdep Kconfig menu entry to Instrumentation support?  It is
currently automatically selected by "Kernel debugging" in Kernel hacking.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>
CC: Ingo Molnar <mingo@xxxxxxxxxx>
CC: Peter Zijlstra <pzijlstr@xxxxxxxxxx>
---
 instrumentation/Makefile            |    4 
 instrumentation/lockdep.c           | 3217 ++++++++++++++++++++++++++++++++++++
 instrumentation/lockdep_internals.h |   78 
 instrumentation/lockdep_proc.c      |  683 +++++++
 kernel/Makefile                     |    4 
 kernel/lockdep.c                    | 3217 ------------------------------------
 kernel/lockdep_internals.h          |   78 
 kernel/lockdep_proc.c               |  683 -------
 8 files changed, 3982 insertions(+), 3982 deletions(-)

Index: linux-2.6-lttng.stable/instrumentation/Makefile
===================================================================
--- linux-2.6-lttng.stable.orig/instrumentation/Makefile	2007-10-29 09:52:30.000000000 -0400
+++ linux-2.6-lttng.stable/instrumentation/Makefile	2007-10-29 09:52:58.000000000 -0400
@@ -6,3 +6,7 @@ obj-y += profile.o
 
 obj-$(CONFIG_KPROBES) += kprobes.o
 obj-$(CONFIG_MARKERS) += marker.o
+obj-$(CONFIG_LOCKDEP) += lockdep.o
+ifeq ($(CONFIG_PROC_FS),y)
+obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
+endif
Index: linux-2.6-lttng.stable/instrumentation/lockdep.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-lttng.stable/instrumentation/lockdep.c	2007-10-29 09:52:35.000000000 -0400
@@ -0,0 +1,3217 @@
+/*
+ * kernel/lockdep.c
+ *
+ * Runtime locking correctness validator
+ *
+ * Started by Ingo Molnar:
+ *
+ *  Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@xxxxxxxxxx>
+ *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@xxxxxxxxxx>
+ *
+ * this code maps all the lock dependencies as they occur in a live kernel
+ * and will warn about the following classes of locking bugs:
+ *
+ * - lock inversion scenarios
+ * - circular lock dependencies
+ * - hardirq/softirq safe/unsafe locking bugs
+ *
+ * Bugs are reported even if the current locking scenario does not cause
+ * any deadlock at this point.
+ *
+ * I.e. if anytime in the past two locks were taken in a different order,
+ * even if it happened for another task, even if those were different
+ * locks (but of the same class as this lock), this code will detect it.
+ *
+ * Thanks to Arjan van de Ven for coming up with the initial idea of
+ * mapping lock dependencies runtime.
+ */
+#include <linux/mutex.h>
+#include <linux/sched.h>
+#include <linux/delay.h>
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/spinlock.h>
+#include <linux/kallsyms.h>
+#include <linux/interrupt.h>
+#include <linux/stacktrace.h>
+#include <linux/debug_locks.h>
+#include <linux/irqflags.h>
+#include <linux/utsname.h>
+#include <linux/hash.h>
+
+#include <asm/sections.h>
+
+#include "lockdep_internals.h"
+
+#ifdef CONFIG_PROVE_LOCKING
+int prove_locking = 1;
+module_param(prove_locking, int, 0644);
+#else
+#define prove_locking 0
+#endif
+
+#ifdef CONFIG_LOCK_STAT
+int lock_stat = 1;
+module_param(lock_stat, int, 0644);
+#else
+#define lock_stat 0
+#endif
+
+/*
+ * lockdep_lock: protects the lockdep graph, the hashes and the
+ *               class/list/hash allocators.
+ *
+ * This is one of the rare exceptions where it's justified
+ * to use a raw spinlock - we really dont want the spinlock
+ * code to recurse back into the lockdep code...
+ */
+static raw_spinlock_t lockdep_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
+
+static int graph_lock(void)
+{
+	__raw_spin_lock(&lockdep_lock);
+	/*
+	 * Make sure that if another CPU detected a bug while
+	 * walking the graph we dont change it (while the other
+	 * CPU is busy printing out stuff with the graph lock
+	 * dropped already)
+	 */
+	if (!debug_locks) {
+		__raw_spin_unlock(&lockdep_lock);
+		return 0;
+	}
+	return 1;
+}
+
+static inline int graph_unlock(void)
+{
+	if (debug_locks && !__raw_spin_is_locked(&lockdep_lock))
+		return DEBUG_LOCKS_WARN_ON(1);
+
+	__raw_spin_unlock(&lockdep_lock);
+	return 0;
+}
+
+/*
+ * Turn lock debugging off and return with 0 if it was off already,
+ * and also release the graph lock:
+ */
+static inline int debug_locks_off_graph_unlock(void)
+{
+	int ret = debug_locks_off();
+
+	__raw_spin_unlock(&lockdep_lock);
+
+	return ret;
+}
+
+static int lockdep_initialized;
+
+unsigned long nr_list_entries;
+static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
+
+/*
+ * All data structures here are protected by the global debug_lock.
+ *
+ * Mutex key structs only get allocated, once during bootup, and never
+ * get freed - this significantly simplifies the debugging code.
+ */
+unsigned long nr_lock_classes;
+static struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
+
+#ifdef CONFIG_LOCK_STAT
+static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats);
+
+static int lock_contention_point(struct lock_class *class, unsigned long ip)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) {
+		if (class->contention_point[i] == 0) {
+			class->contention_point[i] = ip;
+			break;
+		}
+		if (class->contention_point[i] == ip)
+			break;
+	}
+
+	return i;
+}
+
+static void lock_time_inc(struct lock_time *lt, s64 time)
+{
+	if (time > lt->max)
+		lt->max = time;
+
+	if (time < lt->min || !lt->min)
+		lt->min = time;
+
+	lt->total += time;
+	lt->nr++;
+}
+
+static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
+{
+	dst->min += src->min;
+	dst->max += src->max;
+	dst->total += src->total;
+	dst->nr += src->nr;
+}
+
+struct lock_class_stats lock_stats(struct lock_class *class)
+{
+	struct lock_class_stats stats;
+	int cpu, i;
+
+	memset(&stats, 0, sizeof(struct lock_class_stats));
+	for_each_possible_cpu(cpu) {
+		struct lock_class_stats *pcs =
+			&per_cpu(lock_stats, cpu)[class - lock_classes];
+
+		for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++)
+			stats.contention_point[i] += pcs->contention_point[i];
+
+		lock_time_add(&pcs->read_waittime, &stats.read_waittime);
+		lock_time_add(&pcs->write_waittime, &stats.write_waittime);
+
+		lock_time_add(&pcs->read_holdtime, &stats.read_holdtime);
+		lock_time_add(&pcs->write_holdtime, &stats.write_holdtime);
+
+		for (i = 0; i < ARRAY_SIZE(stats.bounces); i++)
+			stats.bounces[i] += pcs->bounces[i];
+	}
+
+	return stats;
+}
+
+void clear_lock_stats(struct lock_class *class)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu) {
+		struct lock_class_stats *cpu_stats =
+			&per_cpu(lock_stats, cpu)[class - lock_classes];
+
+		memset(cpu_stats, 0, sizeof(struct lock_class_stats));
+	}
+	memset(class->contention_point, 0, sizeof(class->contention_point));
+}
+
+static struct lock_class_stats *get_lock_stats(struct lock_class *class)
+{
+	return &get_cpu_var(lock_stats)[class - lock_classes];
+}
+
+static void put_lock_stats(struct lock_class_stats *stats)
+{
+	put_cpu_var(lock_stats);
+}
+
+static void lock_release_holdtime(struct held_lock *hlock)
+{
+	struct lock_class_stats *stats;
+	s64 holdtime;
+
+	if (!lock_stat)
+		return;
+
+	holdtime = sched_clock() - hlock->holdtime_stamp;
+
+	stats = get_lock_stats(hlock->class);
+	if (hlock->read)
+		lock_time_inc(&stats->read_holdtime, holdtime);
+	else
+		lock_time_inc(&stats->write_holdtime, holdtime);
+	put_lock_stats(stats);
+}
+#else
+static inline void lock_release_holdtime(struct held_lock *hlock)
+{
+}
+#endif
+
+/*
+ * We keep a global list of all lock classes. The list only grows,
+ * never shrinks. The list is only accessed with the lockdep
+ * spinlock lock held.
+ */
+LIST_HEAD(all_lock_classes);
+
+/*
+ * The lockdep classes are in a hash-table as well, for fast lookup:
+ */
+#define CLASSHASH_BITS		(MAX_LOCKDEP_KEYS_BITS - 1)
+#define CLASSHASH_SIZE		(1UL << CLASSHASH_BITS)
+#define __classhashfn(key)	hash_long((unsigned long)key, CLASSHASH_BITS)
+#define classhashentry(key)	(classhash_table + __classhashfn((key)))
+
+static struct list_head classhash_table[CLASSHASH_SIZE];
+
+/*
+ * We put the lock dependency chains into a hash-table as well, to cache
+ * their existence:
+ */
+#define CHAINHASH_BITS		(MAX_LOCKDEP_CHAINS_BITS-1)
+#define CHAINHASH_SIZE		(1UL << CHAINHASH_BITS)
+#define __chainhashfn(chain)	hash_long(chain, CHAINHASH_BITS)
+#define chainhashentry(chain)	(chainhash_table + __chainhashfn((chain)))
+
+static struct list_head chainhash_table[CHAINHASH_SIZE];
+
+/*
+ * The hash key of the lock dependency chains is a hash itself too:
+ * it's a hash of all locks taken up to that lock, including that lock.
+ * It's a 64-bit hash, because it's important for the keys to be
+ * unique.
+ */
+#define iterate_chain_key(key1, key2) \
+	(((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \
+	((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \
+	(key2))
+
+void lockdep_off(void)
+{
+	current->lockdep_recursion++;
+}
+
+EXPORT_SYMBOL(lockdep_off);
+
+void lockdep_on(void)
+{
+	current->lockdep_recursion--;
+}
+
+EXPORT_SYMBOL(lockdep_on);
+
+/*
+ * Debugging switches:
+ */
+
+#define VERBOSE			0
+#define VERY_VERBOSE		0
+
+#if VERBOSE
+# define HARDIRQ_VERBOSE	1
+# define SOFTIRQ_VERBOSE	1
+#else
+# define HARDIRQ_VERBOSE	0
+# define SOFTIRQ_VERBOSE	0
+#endif
+
+#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE
+/*
+ * Quick filtering for interesting events:
+ */
+static int class_filter(struct lock_class *class)
+{
+#if 0
+	/* Example */
+	if (class->name_version == 1 &&
+			!strcmp(class->name, "lockname"))
+		return 1;
+	if (class->name_version == 1 &&
+			!strcmp(class->name, "&struct->lockfield"))
+		return 1;
+#endif
+	/* Filter everything else. 1 would be to allow everything else */
+	return 0;
+}
+#endif
+
+static int verbose(struct lock_class *class)
+{
+#if VERBOSE
+	return class_filter(class);
+#endif
+	return 0;
+}
+
+/*
+ * Stack-trace: tightly packed array of stack backtrace
+ * addresses. Protected by the graph_lock.
+ */
+unsigned long nr_stack_trace_entries;
+static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
+
+static int save_trace(struct stack_trace *trace)
+{
+	trace->nr_entries = 0;
+	trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
+	trace->entries = stack_trace + nr_stack_trace_entries;
+
+	trace->skip = 3;
+
+	save_stack_trace(trace);
+
+	trace->max_entries = trace->nr_entries;
+
+	nr_stack_trace_entries += trace->nr_entries;
+
+	if (nr_stack_trace_entries == MAX_STACK_TRACE_ENTRIES) {
+		if (!debug_locks_off_graph_unlock())
+			return 0;
+
+		printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n");
+		printk("turning off the locking correctness validator.\n");
+		dump_stack();
+
+		return 0;
+	}
+
+	return 1;
+}
+
+unsigned int nr_hardirq_chains;
+unsigned int nr_softirq_chains;
+unsigned int nr_process_chains;
+unsigned int max_lockdep_depth;
+unsigned int max_recursion_depth;
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+/*
+ * We cannot printk in early bootup code. Not even early_printk()
+ * might work. So we mark any initialization errors and printk
+ * about it later on, in lockdep_info().
+ */
+static int lockdep_init_error;
+static unsigned long lockdep_init_trace_data[20];
+static struct stack_trace lockdep_init_trace = {
+	.max_entries = ARRAY_SIZE(lockdep_init_trace_data),
+	.entries = lockdep_init_trace_data,
+};
+
+/*
+ * Various lockdep statistics:
+ */
+atomic_t chain_lookup_hits;
+atomic_t chain_lookup_misses;
+atomic_t hardirqs_on_events;
+atomic_t hardirqs_off_events;
+atomic_t redundant_hardirqs_on;
+atomic_t redundant_hardirqs_off;
+atomic_t softirqs_on_events;
+atomic_t softirqs_off_events;
+atomic_t redundant_softirqs_on;
+atomic_t redundant_softirqs_off;
+atomic_t nr_unused_locks;
+atomic_t nr_cyclic_checks;
+atomic_t nr_cyclic_check_recursions;
+atomic_t nr_find_usage_forwards_checks;
+atomic_t nr_find_usage_forwards_recursions;
+atomic_t nr_find_usage_backwards_checks;
+atomic_t nr_find_usage_backwards_recursions;
+# define debug_atomic_inc(ptr)		atomic_inc(ptr)
+# define debug_atomic_dec(ptr)		atomic_dec(ptr)
+# define debug_atomic_read(ptr)		atomic_read(ptr)
+#else
+# define debug_atomic_inc(ptr)		do { } while (0)
+# define debug_atomic_dec(ptr)		do { } while (0)
+# define debug_atomic_read(ptr)		0
+#endif
+
+/*
+ * Locking printouts:
+ */
+
+static const char *usage_str[] =
+{
+	[LOCK_USED] =			"initial-use ",
+	[LOCK_USED_IN_HARDIRQ] =	"in-hardirq-W",
+	[LOCK_USED_IN_SOFTIRQ] =	"in-softirq-W",
+	[LOCK_ENABLED_SOFTIRQS] =	"softirq-on-W",
+	[LOCK_ENABLED_HARDIRQS] =	"hardirq-on-W",
+	[LOCK_USED_IN_HARDIRQ_READ] =	"in-hardirq-R",
+	[LOCK_USED_IN_SOFTIRQ_READ] =	"in-softirq-R",
+	[LOCK_ENABLED_SOFTIRQS_READ] =	"softirq-on-R",
+	[LOCK_ENABLED_HARDIRQS_READ] =	"hardirq-on-R",
+};
+
+const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
+{
+	return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
+}
+
+void
+get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4)
+{
+	*c1 = '.', *c2 = '.', *c3 = '.', *c4 = '.';
+
+	if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
+		*c1 = '+';
+	else
+		if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
+			*c1 = '-';
+
+	if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
+		*c2 = '+';
+	else
+		if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
+			*c2 = '-';
+
+	if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
+		*c3 = '-';
+	if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) {
+		*c3 = '+';
+		if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
+			*c3 = '?';
+	}
+
+	if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
+		*c4 = '-';
+	if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) {
+		*c4 = '+';
+		if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
+			*c4 = '?';
+	}
+}
+
+static void print_lock_name(struct lock_class *class)
+{
+	char str[KSYM_NAME_LEN], c1, c2, c3, c4;
+	const char *name;
+
+	get_usage_chars(class, &c1, &c2, &c3, &c4);
+
+	name = class->name;
+	if (!name) {
+		name = __get_key_name(class->key, str);
+		printk(" (%s", name);
+	} else {
+		printk(" (%s", name);
+		if (class->name_version > 1)
+			printk("#%d", class->name_version);
+		if (class->subclass)
+			printk("/%d", class->subclass);
+	}
+	printk("){%c%c%c%c}", c1, c2, c3, c4);
+}
+
+static void print_lockdep_cache(struct lockdep_map *lock)
+{
+	const char *name;
+	char str[KSYM_NAME_LEN];
+
+	name = lock->name;
+	if (!name)
+		name = __get_key_name(lock->key->subkeys, str);
+
+	printk("%s", name);
+}
+
+static void print_lock(struct held_lock *hlock)
+{
+	print_lock_name(hlock->class);
+	printk(", at: ");
+	print_ip_sym(hlock->acquire_ip);
+}
+
+static void lockdep_print_held_locks(struct task_struct *curr)
+{
+	int i, depth = curr->lockdep_depth;
+
+	if (!depth) {
+		printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr));
+		return;
+	}
+	printk("%d lock%s held by %s/%d:\n",
+		depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr));
+
+	for (i = 0; i < depth; i++) {
+		printk(" #%d: ", i);
+		print_lock(curr->held_locks + i);
+	}
+}
+
+static void print_lock_class_header(struct lock_class *class, int depth)
+{
+	int bit;
+
+	printk("%*s->", depth, "");
+	print_lock_name(class);
+	printk(" ops: %lu", class->ops);
+	printk(" {\n");
+
+	for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
+		if (class->usage_mask & (1 << bit)) {
+			int len = depth;
+
+			len += printk("%*s   %s", depth, "", usage_str[bit]);
+			len += printk(" at:\n");
+			print_stack_trace(class->usage_traces + bit, len);
+		}
+	}
+	printk("%*s }\n", depth, "");
+
+	printk("%*s ... key      at: ",depth,"");
+	print_ip_sym((unsigned long)class->key);
+}
+
+/*
+ * printk all lock dependencies starting at <entry>:
+ */
+static void print_lock_dependencies(struct lock_class *class, int depth)
+{
+	struct lock_list *entry;
+
+	if (DEBUG_LOCKS_WARN_ON(depth >= 20))
+		return;
+
+	print_lock_class_header(class, depth);
+
+	list_for_each_entry(entry, &class->locks_after, entry) {
+		if (DEBUG_LOCKS_WARN_ON(!entry->class))
+			return;
+
+		print_lock_dependencies(entry->class, depth + 1);
+
+		printk("%*s ... acquired at:\n",depth,"");
+		print_stack_trace(&entry->trace, 2);
+		printk("\n");
+	}
+}
+
+static void print_kernel_version(void)
+{
+	printk("%s %.*s\n", init_utsname()->release,
+		(int)strcspn(init_utsname()->version, " "),
+		init_utsname()->version);
+}
+
+static int very_verbose(struct lock_class *class)
+{
+#if VERY_VERBOSE
+	return class_filter(class);
+#endif
+	return 0;
+}
+
+/*
+ * Is this the address of a static object:
+ */
+static int static_obj(void *obj)
+{
+	unsigned long start = (unsigned long) &_stext,
+		      end   = (unsigned long) &_end,
+		      addr  = (unsigned long) obj;
+#ifdef CONFIG_SMP
+	int i;
+#endif
+
+	/*
+	 * static variable?
+	 */
+	if ((addr >= start) && (addr < end))
+		return 1;
+
+#ifdef CONFIG_SMP
+	/*
+	 * percpu var?
+	 */
+	for_each_possible_cpu(i) {
+		start = (unsigned long) &__per_cpu_start + per_cpu_offset(i);
+		end   = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM
+					+ per_cpu_offset(i);
+
+		if ((addr >= start) && (addr < end))
+			return 1;
+	}
+#endif
+
+	/*
+	 * module var?
+	 */
+	return is_module_address(addr);
+}
+
+/*
+ * To make lock name printouts unique, we calculate a unique
+ * class->name_version generation counter:
+ */
+static int count_matching_names(struct lock_class *new_class)
+{
+	struct lock_class *class;
+	int count = 0;
+
+	if (!new_class->name)
+		return 0;
+
+	list_for_each_entry(class, &all_lock_classes, lock_entry) {
+		if (new_class->key - new_class->subclass == class->key)
+			return class->name_version;
+		if (class->name && !strcmp(class->name, new_class->name))
+			count = max(count, class->name_version);
+	}
+
+	return count + 1;
+}
+
+/*
+ * Register a lock's class in the hash-table, if the class is not present
+ * yet. Otherwise we look it up. We cache the result in the lock object
+ * itself, so actual lookup of the hash should be once per lock object.
+ */
+static inline struct lock_class *
+look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
+{
+	struct lockdep_subclass_key *key;
+	struct list_head *hash_head;
+	struct lock_class *class;
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+	/*
+	 * If the architecture calls into lockdep before initializing
+	 * the hashes then we'll warn about it later. (we cannot printk
+	 * right now)
+	 */
+	if (unlikely(!lockdep_initialized)) {
+		lockdep_init();
+		lockdep_init_error = 1;
+		save_stack_trace(&lockdep_init_trace);
+	}
+#endif
+
+	/*
+	 * Static locks do not have their class-keys yet - for them the key
+	 * is the lock object itself:
+	 */
+	if (unlikely(!lock->key))
+		lock->key = (void *)lock;
+
+	/*
+	 * NOTE: the class-key must be unique. For dynamic locks, a static
+	 * lock_class_key variable is passed in through the mutex_init()
+	 * (or spin_lock_init()) call - which acts as the key. For static
+	 * locks we use the lock object itself as the key.
+	 */
+	BUILD_BUG_ON(sizeof(struct lock_class_key) >
+			sizeof(struct lockdep_map));
+
+	key = lock->key->subkeys + subclass;
+
+	hash_head = classhashentry(key);
+
+	/*
+	 * We can walk the hash lockfree, because the hash only
+	 * grows, and we are careful when adding entries to the end:
+	 */
+	list_for_each_entry(class, hash_head, hash_entry) {
+		if (class->key == key) {
+			WARN_ON_ONCE(class->name != lock->name);
+			return class;
+		}
+	}
+
+	return NULL;
+}
+
+/*
+ * Register a lock's class in the hash-table, if the class is not present
+ * yet. Otherwise we look it up. We cache the result in the lock object
+ * itself, so actual lookup of the hash should be once per lock object.
+ */
+static inline struct lock_class *
+register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
+{
+	struct lockdep_subclass_key *key;
+	struct list_head *hash_head;
+	struct lock_class *class;
+	unsigned long flags;
+
+	class = look_up_lock_class(lock, subclass);
+	if (likely(class))
+		return class;
+
+	/*
+	 * Debug-check: all keys must be persistent!
+ 	 */
+	if (!static_obj(lock->key)) {
+		debug_locks_off();
+		printk("INFO: trying to register non-static key.\n");
+		printk("the code is fine but needs lockdep annotation.\n");
+		printk("turning off the locking correctness validator.\n");
+		dump_stack();
+
+		return NULL;
+	}
+
+	key = lock->key->subkeys + subclass;
+	hash_head = classhashentry(key);
+
+	raw_local_irq_save(flags);
+	if (!graph_lock()) {
+		raw_local_irq_restore(flags);
+		return NULL;
+	}
+	/*
+	 * We have to do the hash-walk again, to avoid races
+	 * with another CPU:
+	 */
+	list_for_each_entry(class, hash_head, hash_entry)
+		if (class->key == key)
+			goto out_unlock_set;
+	/*
+	 * Allocate a new key from the static array, and add it to
+	 * the hash:
+	 */
+	if (nr_lock_classes >= MAX_LOCKDEP_KEYS) {
+		if (!debug_locks_off_graph_unlock()) {
+			raw_local_irq_restore(flags);
+			return NULL;
+		}
+		raw_local_irq_restore(flags);
+
+		printk("BUG: MAX_LOCKDEP_KEYS too low!\n");
+		printk("turning off the locking correctness validator.\n");
+		return NULL;
+	}
+	class = lock_classes + nr_lock_classes++;
+	debug_atomic_inc(&nr_unused_locks);
+	class->key = key;
+	class->name = lock->name;
+	class->subclass = subclass;
+	INIT_LIST_HEAD(&class->lock_entry);
+	INIT_LIST_HEAD(&class->locks_before);
+	INIT_LIST_HEAD(&class->locks_after);
+	class->name_version = count_matching_names(class);
+	/*
+	 * We use RCU's safe list-add method to make
+	 * parallel walking of the hash-list safe:
+	 */
+	list_add_tail_rcu(&class->hash_entry, hash_head);
+
+	if (verbose(class)) {
+		graph_unlock();
+		raw_local_irq_restore(flags);
+
+		printk("\nnew class %p: %s", class->key, class->name);
+		if (class->name_version > 1)
+			printk("#%d", class->name_version);
+		printk("\n");
+		dump_stack();
+
+		raw_local_irq_save(flags);
+		if (!graph_lock()) {
+			raw_local_irq_restore(flags);
+			return NULL;
+		}
+	}
+out_unlock_set:
+	graph_unlock();
+	raw_local_irq_restore(flags);
+
+	if (!subclass || force)
+		lock->class_cache = class;
+
+	if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
+		return NULL;
+
+	return class;
+}
+
+#ifdef CONFIG_PROVE_LOCKING
+/*
+ * Allocate a lockdep entry. (assumes the graph_lock held, returns
+ * with NULL on failure)
+ */
+static struct lock_list *alloc_list_entry(void)
+{
+	if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) {
+		if (!debug_locks_off_graph_unlock())
+			return NULL;
+
+		printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n");
+		printk("turning off the locking correctness validator.\n");
+		return NULL;
+	}
+	return list_entries + nr_list_entries++;
+}
+
+/*
+ * Add a new dependency to the head of the list:
+ */
+static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
+			    struct list_head *head, unsigned long ip, int distance)
+{
+	struct lock_list *entry;
+	/*
+	 * Lock not present yet - get a new dependency struct and
+	 * add it to the list:
+	 */
+	entry = alloc_list_entry();
+	if (!entry)
+		return 0;
+
+	entry->class = this;
+	entry->distance = distance;
+	if (!save_trace(&entry->trace))
+		return 0;
+
+	/*
+	 * Since we never remove from the dependency list, the list can
+	 * be walked lockless by other CPUs, it's only allocation
+	 * that must be protected by the spinlock. But this also means
+	 * we must make new entries visible only once writes to the
+	 * entry become visible - hence the RCU op:
+	 */
+	list_add_tail_rcu(&entry->entry, head);
+
+	return 1;
+}
+
+/*
+ * Recursive, forwards-direction lock-dependency checking, used for
+ * both noncyclic checking and for hardirq-unsafe/softirq-unsafe
+ * checking.
+ *
+ * (to keep the stackframe of the recursive functions small we
+ *  use these global variables, and we also mark various helper
+ *  functions as noinline.)
+ */
+static struct held_lock *check_source, *check_target;
+
+/*
+ * Print a dependency chain entry (this is only done when a deadlock
+ * has been detected):
+ */
+static noinline int
+print_circular_bug_entry(struct lock_list *target, unsigned int depth)
+{
+	if (debug_locks_silent)
+		return 0;
+	printk("\n-> #%u", depth);
+	print_lock_name(target->class);
+	printk(":\n");
+	print_stack_trace(&target->trace, 6);
+
+	return 0;
+}
+
+/*
+ * When a circular dependency is detected, print the
+ * header first:
+ */
+static noinline int
+print_circular_bug_header(struct lock_list *entry, unsigned int depth)
+{
+	struct task_struct *curr = current;
+
+	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+		return 0;
+
+	printk("\n=======================================================\n");
+	printk(  "[ INFO: possible circular locking dependency detected ]\n");
+	print_kernel_version();
+	printk(  "-------------------------------------------------------\n");
+	printk("%s/%d is trying to acquire lock:\n",
+		curr->comm, task_pid_nr(curr));
+	print_lock(check_source);
+	printk("\nbut task is already holding lock:\n");
+	print_lock(check_target);
+	printk("\nwhich lock already depends on the new lock.\n\n");
+	printk("\nthe existing dependency chain (in reverse order) is:\n");
+
+	print_circular_bug_entry(entry, depth);
+
+	return 0;
+}
+
+static noinline int print_circular_bug_tail(void)
+{
+	struct task_struct *curr = current;
+	struct lock_list this;
+
+	if (debug_locks_silent)
+		return 0;
+
+	this.class = check_source->class;
+	if (!save_trace(&this.trace))
+		return 0;
+
+	print_circular_bug_entry(&this, 0);
+
+	printk("\nother info that might help us debug this:\n\n");
+	lockdep_print_held_locks(curr);
+
+	printk("\nstack backtrace:\n");
+	dump_stack();
+
+	return 0;
+}
+
+#define RECURSION_LIMIT 40
+
+static int noinline print_infinite_recursion_bug(void)
+{
+	if (!debug_locks_off_graph_unlock())
+		return 0;
+
+	WARN_ON(1);
+
+	return 0;
+}
+
+/*
+ * Prove that the dependency graph starting at <entry> can not
+ * lead to <target>. Print an error and return 0 if it does.
+ */
+static noinline int
+check_noncircular(struct lock_class *source, unsigned int depth)
+{
+	struct lock_list *entry;
+
+	debug_atomic_inc(&nr_cyclic_check_recursions);
+	if (depth > max_recursion_depth)
+		max_recursion_depth = depth;
+	if (depth >= RECURSION_LIMIT)
+		return print_infinite_recursion_bug();
+	/*
+	 * Check this lock's dependency list:
+	 */
+	list_for_each_entry(entry, &source->locks_after, entry) {
+		if (entry->class == check_target->class)
+			return print_circular_bug_header(entry, depth+1);
+		debug_atomic_inc(&nr_cyclic_checks);
+		if (!check_noncircular(entry->class, depth+1))
+			return print_circular_bug_entry(entry, depth+1);
+	}
+	return 1;
+}
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+/*
+ * Forwards and backwards subgraph searching, for the purposes of
+ * proving that two subgraphs can be connected by a new dependency
+ * without creating any illegal irq-safe -> irq-unsafe lock dependency.
+ */
+static enum lock_usage_bit find_usage_bit;
+static struct lock_class *forwards_match, *backwards_match;
+
+/*
+ * Find a node in the forwards-direction dependency sub-graph starting
+ * at <source> that matches <find_usage_bit>.
+ *
+ * Return 2 if such a node exists in the subgraph, and put that node
+ * into <forwards_match>.
+ *
+ * Return 1 otherwise and keep <forwards_match> unchanged.
+ * Return 0 on error.
+ */
+static noinline int
+find_usage_forwards(struct lock_class *source, unsigned int depth)
+{
+	struct lock_list *entry;
+	int ret;
+
+	if (depth > max_recursion_depth)
+		max_recursion_depth = depth;
+	if (depth >= RECURSION_LIMIT)
+		return print_infinite_recursion_bug();
+
+	debug_atomic_inc(&nr_find_usage_forwards_checks);
+	if (source->usage_mask & (1 << find_usage_bit)) {
+		forwards_match = source;
+		return 2;
+	}
+
+	/*
+	 * Check this lock's dependency list:
+	 */
+	list_for_each_entry(entry, &source->locks_after, entry) {
+		debug_atomic_inc(&nr_find_usage_forwards_recursions);
+		ret = find_usage_forwards(entry->class, depth+1);
+		if (ret == 2 || ret == 0)
+			return ret;
+	}
+	return 1;
+}
+
+/*
+ * Find a node in the backwards-direction dependency sub-graph starting
+ * at <source> that matches <find_usage_bit>.
+ *
+ * Return 2 if such a node exists in the subgraph, and put that node
+ * into <backwards_match>.
+ *
+ * Return 1 otherwise and keep <backwards_match> unchanged.
+ * Return 0 on error.
+ */
+static noinline int
+find_usage_backwards(struct lock_class *source, unsigned int depth)
+{
+	struct lock_list *entry;
+	int ret;
+
+	if (!__raw_spin_is_locked(&lockdep_lock))
+		return DEBUG_LOCKS_WARN_ON(1);
+
+	if (depth > max_recursion_depth)
+		max_recursion_depth = depth;
+	if (depth >= RECURSION_LIMIT)
+		return print_infinite_recursion_bug();
+
+	debug_atomic_inc(&nr_find_usage_backwards_checks);
+	if (source->usage_mask & (1 << find_usage_bit)) {
+		backwards_match = source;
+		return 2;
+	}
+
+	/*
+	 * Check this lock's dependency list:
+	 */
+	list_for_each_entry(entry, &source->locks_before, entry) {
+		debug_atomic_inc(&nr_find_usage_backwards_recursions);
+		ret = find_usage_backwards(entry->class, depth+1);
+		if (ret == 2 || ret == 0)
+			return ret;
+	}
+	return 1;
+}
+
+static int
+print_bad_irq_dependency(struct task_struct *curr,
+			 struct held_lock *prev,
+			 struct held_lock *next,
+			 enum lock_usage_bit bit1,
+			 enum lock_usage_bit bit2,
+			 const char *irqclass)
+{
+	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+		return 0;
+
+	printk("\n======================================================\n");
+	printk(  "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
+		irqclass, irqclass);
+	print_kernel_version();
+	printk(  "------------------------------------------------------\n");
+	printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
+		curr->comm, task_pid_nr(curr),
+		curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT,
+		curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT,
+		curr->hardirqs_enabled,
+		curr->softirqs_enabled);
+	print_lock(next);
+
+	printk("\nand this task is already holding:\n");
+	print_lock(prev);
+	printk("which would create a new lock dependency:\n");
+	print_lock_name(prev->class);
+	printk(" ->");
+	print_lock_name(next->class);
+	printk("\n");
+
+	printk("\nbut this new dependency connects a %s-irq-safe lock:\n",
+		irqclass);
+	print_lock_name(backwards_match);
+	printk("\n... which became %s-irq-safe at:\n", irqclass);
+
+	print_stack_trace(backwards_match->usage_traces + bit1, 1);
+
+	printk("\nto a %s-irq-unsafe lock:\n", irqclass);
+	print_lock_name(forwards_match);
+	printk("\n... which became %s-irq-unsafe at:\n", irqclass);
+	printk("...");
+
+	print_stack_trace(forwards_match->usage_traces + bit2, 1);
+
+	printk("\nother info that might help us debug this:\n\n");
+	lockdep_print_held_locks(curr);
+
+	printk("\nthe %s-irq-safe lock's dependencies:\n", irqclass);
+	print_lock_dependencies(backwards_match, 0);
+
+	printk("\nthe %s-irq-unsafe lock's dependencies:\n", irqclass);
+	print_lock_dependencies(forwards_match, 0);
+
+	printk("\nstack backtrace:\n");
+	dump_stack();
+
+	return 0;
+}
+
+static int
+check_usage(struct task_struct *curr, struct held_lock *prev,
+	    struct held_lock *next, enum lock_usage_bit bit_backwards,
+	    enum lock_usage_bit bit_forwards, const char *irqclass)
+{
+	int ret;
+
+	find_usage_bit = bit_backwards;
+	/* fills in <backwards_match> */
+	ret = find_usage_backwards(prev->class, 0);
+	if (!ret || ret == 1)
+		return ret;
+
+	find_usage_bit = bit_forwards;
+	ret = find_usage_forwards(next->class, 0);
+	if (!ret || ret == 1)
+		return ret;
+	/* ret == 2 */
+	return print_bad_irq_dependency(curr, prev, next,
+			bit_backwards, bit_forwards, irqclass);
+}
+
+static int
+check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
+		struct held_lock *next)
+{
+	/*
+	 * Prove that the new dependency does not connect a hardirq-safe
+	 * lock with a hardirq-unsafe lock - to achieve this we search
+	 * the backwards-subgraph starting at <prev>, and the
+	 * forwards-subgraph starting at <next>:
+	 */
+	if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ,
+					LOCK_ENABLED_HARDIRQS, "hard"))
+		return 0;
+
+	/*
+	 * Prove that the new dependency does not connect a hardirq-safe-read
+	 * lock with a hardirq-unsafe lock - to achieve this we search
+	 * the backwards-subgraph starting at <prev>, and the
+	 * forwards-subgraph starting at <next>:
+	 */
+	if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ,
+					LOCK_ENABLED_HARDIRQS, "hard-read"))
+		return 0;
+
+	/*
+	 * Prove that the new dependency does not connect a softirq-safe
+	 * lock with a softirq-unsafe lock - to achieve this we search
+	 * the backwards-subgraph starting at <prev>, and the
+	 * forwards-subgraph starting at <next>:
+	 */
+	if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ,
+					LOCK_ENABLED_SOFTIRQS, "soft"))
+		return 0;
+	/*
+	 * Prove that the new dependency does not connect a softirq-safe-read
+	 * lock with a softirq-unsafe lock - to achieve this we search
+	 * the backwards-subgraph starting at <prev>, and the
+	 * forwards-subgraph starting at <next>:
+	 */
+	if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ,
+					LOCK_ENABLED_SOFTIRQS, "soft"))
+		return 0;
+
+	return 1;
+}
+
+static void inc_chains(void)
+{
+	if (current->hardirq_context)
+		nr_hardirq_chains++;
+	else {
+		if (current->softirq_context)
+			nr_softirq_chains++;
+		else
+			nr_process_chains++;
+	}
+}
+
+#else
+
+static inline int
+check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
+		struct held_lock *next)
+{
+	return 1;
+}
+
+static inline void inc_chains(void)
+{
+	nr_process_chains++;
+}
+
+#endif
+
+static int
+print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
+		   struct held_lock *next)
+{
+	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+		return 0;
+
+	printk("\n=============================================\n");
+	printk(  "[ INFO: possible recursive locking detected ]\n");
+	print_kernel_version();
+	printk(  "---------------------------------------------\n");
+	printk("%s/%d is trying to acquire lock:\n",
+		curr->comm, task_pid_nr(curr));
+	print_lock(next);
+	printk("\nbut task is already holding lock:\n");
+	print_lock(prev);
+
+	printk("\nother info that might help us debug this:\n");
+	lockdep_print_held_locks(curr);
+
+	printk("\nstack backtrace:\n");
+	dump_stack();
+
+	return 0;
+}
+
+/*
+ * Check whether we are holding such a class already.
+ *
+ * (Note that this has to be done separately, because the graph cannot
+ * detect such classes of deadlocks.)
+ *
+ * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read
+ */
+static int
+check_deadlock(struct task_struct *curr, struct held_lock *next,
+	       struct lockdep_map *next_instance, int read)
+{
+	struct held_lock *prev;
+	int i;
+
+	for (i = 0; i < curr->lockdep_depth; i++) {
+		prev = curr->held_locks + i;
+		if (prev->class != next->class)
+			continue;
+		/*
+		 * Allow read-after-read recursion of the same
+		 * lock class (i.e. read_lock(lock)+read_lock(lock)):
+		 */
+		if ((read == 2) && prev->read)
+			return 2;
+		return print_deadlock_bug(curr, prev, next);
+	}
+	return 1;
+}
+
+/*
+ * There was a chain-cache miss, and we are about to add a new dependency
+ * to a previous lock. We recursively validate the following rules:
+ *
+ *  - would the adding of the <prev> -> <next> dependency create a
+ *    circular dependency in the graph? [== circular deadlock]
+ *
+ *  - does the new prev->next dependency connect any hardirq-safe lock
+ *    (in the full backwards-subgraph starting at <prev>) with any
+ *    hardirq-unsafe lock (in the full forwards-subgraph starting at
+ *    <next>)? [== illegal lock inversion with hardirq contexts]
+ *
+ *  - does the new prev->next dependency connect any softirq-safe lock
+ *    (in the full backwards-subgraph starting at <prev>) with any
+ *    softirq-unsafe lock (in the full forwards-subgraph starting at
+ *    <next>)? [== illegal lock inversion with softirq contexts]
+ *
+ * any of these scenarios could lead to a deadlock.
+ *
+ * Then if all the validations pass, we add the forwards and backwards
+ * dependency.
+ */
+static int
+check_prev_add(struct task_struct *curr, struct held_lock *prev,
+	       struct held_lock *next, int distance)
+{
+	struct lock_list *entry;
+	int ret;
+
+	/*
+	 * Prove that the new <prev> -> <next> dependency would not
+	 * create a circular dependency in the graph. (We do this by
+	 * forward-recursing into the graph starting at <next>, and
+	 * checking whether we can reach <prev>.)
+	 *
+	 * We are using global variables to control the recursion, to
+	 * keep the stackframe size of the recursive functions low:
+	 */
+	check_source = next;
+	check_target = prev;
+	if (!(check_noncircular(next->class, 0)))
+		return print_circular_bug_tail();
+
+	if (!check_prev_add_irq(curr, prev, next))
+		return 0;
+
+	/*
+	 * For recursive read-locks we do all the dependency checks,
+	 * but we dont store read-triggered dependencies (only
+	 * write-triggered dependencies). This ensures that only the
+	 * write-side dependencies matter, and that if for example a
+	 * write-lock never takes any other locks, then the reads are
+	 * equivalent to a NOP.
+	 */
+	if (next->read == 2 || prev->read == 2)
+		return 1;
+	/*
+	 * Is the <prev> -> <next> dependency already present?
+	 *
+	 * (this may occur even though this is a new chain: consider
+	 *  e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3
+	 *  chains - the second one will be new, but L1 already has
+	 *  L2 added to its dependency list, due to the first chain.)
+	 */
+	list_for_each_entry(entry, &prev->class->locks_after, entry) {
+		if (entry->class == next->class) {
+			if (distance == 1)
+				entry->distance = 1;
+			return 2;
+		}
+	}
+
+	/*
+	 * Ok, all validations passed, add the new lock
+	 * to the previous lock's dependency list:
+	 */
+	ret = add_lock_to_list(prev->class, next->class,
+			       &prev->class->locks_after, next->acquire_ip, distance);
+
+	if (!ret)
+		return 0;
+
+	ret = add_lock_to_list(next->class, prev->class,
+			       &next->class->locks_before, next->acquire_ip, distance);
+	if (!ret)
+		return 0;
+
+	/*
+	 * Debugging printouts:
+	 */
+	if (verbose(prev->class) || verbose(next->class)) {
+		graph_unlock();
+		printk("\n new dependency: ");
+		print_lock_name(prev->class);
+		printk(" => ");
+		print_lock_name(next->class);
+		printk("\n");
+		dump_stack();
+		return graph_lock();
+	}
+	return 1;
+}
+
+/*
+ * Add the dependency to all directly-previous locks that are 'relevant'.
+ * The ones that are relevant are (in increasing distance from curr):
+ * all consecutive trylock entries and the final non-trylock entry - or
+ * the end of this context's lock-chain - whichever comes first.
+ */
+static int
+check_prevs_add(struct task_struct *curr, struct held_lock *next)
+{
+	int depth = curr->lockdep_depth;
+	struct held_lock *hlock;
+
+	/*
+	 * Debugging checks.
+	 *
+	 * Depth must not be zero for a non-head lock:
+	 */
+	if (!depth)
+		goto out_bug;
+	/*
+	 * At least two relevant locks must exist for this
+	 * to be a head:
+	 */
+	if (curr->held_locks[depth].irq_context !=
+			curr->held_locks[depth-1].irq_context)
+		goto out_bug;
+
+	for (;;) {
+		int distance = curr->lockdep_depth - depth + 1;
+		hlock = curr->held_locks + depth-1;
+		/*
+		 * Only non-recursive-read entries get new dependencies
+		 * added:
+		 */
+		if (hlock->read != 2) {
+			if (!check_prev_add(curr, hlock, next, distance))
+				return 0;
+			/*
+			 * Stop after the first non-trylock entry,
+			 * as non-trylock entries have added their
+			 * own direct dependencies already, so this
+			 * lock is connected to them indirectly:
+			 */
+			if (!hlock->trylock)
+				break;
+		}
+		depth--;
+		/*
+		 * End of lock-stack?
+		 */
+		if (!depth)
+			break;
+		/*
+		 * Stop the search if we cross into another context:
+		 */
+		if (curr->held_locks[depth].irq_context !=
+				curr->held_locks[depth-1].irq_context)
+			break;
+	}
+	return 1;
+out_bug:
+	if (!debug_locks_off_graph_unlock())
+		return 0;
+
+	WARN_ON(1);
+
+	return 0;
+}
+
+unsigned long nr_lock_chains;
+static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
+
+/*
+ * Look up a dependency chain. If the key is not present yet then
+ * add it and return 1 - in this case the new dependency chain is
+ * validated. If the key is already hashed, return 0.
+ * (On return with 1 graph_lock is held.)
+ */
+static inline int lookup_chain_cache(u64 chain_key, struct lock_class *class)
+{
+	struct list_head *hash_head = chainhashentry(chain_key);
+	struct lock_chain *chain;
+
+	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+		return 0;
+	/*
+	 * We can walk it lock-free, because entries only get added
+	 * to the hash:
+	 */
+	list_for_each_entry(chain, hash_head, entry) {
+		if (chain->chain_key == chain_key) {
+cache_hit:
+			debug_atomic_inc(&chain_lookup_hits);
+			if (very_verbose(class))
+				printk("\nhash chain already cached, key: "
+					"%016Lx tail class: [%p] %s\n",
+					(unsigned long long)chain_key,
+					class->key, class->name);
+			return 0;
+		}
+	}
+	if (very_verbose(class))
+		printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n",
+			(unsigned long long)chain_key, class->key, class->name);
+	/*
+	 * Allocate a new chain entry from the static array, and add
+	 * it to the hash:
+	 */
+	if (!graph_lock())
+		return 0;
+	/*
+	 * We have to walk the chain again locked - to avoid duplicates:
+	 */
+	list_for_each_entry(chain, hash_head, entry) {
+		if (chain->chain_key == chain_key) {
+			graph_unlock();
+			goto cache_hit;
+		}
+	}
+	if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) {
+		if (!debug_locks_off_graph_unlock())
+			return 0;
+
+		printk("BUG: MAX_LOCKDEP_CHAINS too low!\n");
+		printk("turning off the locking correctness validator.\n");
+		return 0;
+	}
+	chain = lock_chains + nr_lock_chains++;
+	chain->chain_key = chain_key;
+	list_add_tail_rcu(&chain->entry, hash_head);
+	debug_atomic_inc(&chain_lookup_misses);
+	inc_chains();
+
+	return 1;
+}
+
+static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
+		struct held_lock *hlock, int chain_head, u64 chain_key)
+{
+	/*
+	 * Trylock needs to maintain the stack of held locks, but it
+	 * does not add new dependencies, because trylock can be done
+	 * in any order.
+	 *
+	 * We look up the chain_key and do the O(N^2) check and update of
+	 * the dependencies only if this is a new dependency chain.
+	 * (If lookup_chain_cache() returns with 1 it acquires
+	 * graph_lock for us)
+	 */
+	if (!hlock->trylock && (hlock->check == 2) &&
+			lookup_chain_cache(chain_key, hlock->class)) {
+		/*
+		 * Check whether last held lock:
+		 *
+		 * - is irq-safe, if this lock is irq-unsafe
+		 * - is softirq-safe, if this lock is hardirq-unsafe
+		 *
+		 * And check whether the new lock's dependency graph
+		 * could lead back to the previous lock.
+		 *
+		 * any of these scenarios could lead to a deadlock. If
+		 * All validations
+		 */
+		int ret = check_deadlock(curr, hlock, lock, hlock->read);
+
+		if (!ret)
+			return 0;
+		/*
+		 * Mark recursive read, as we jump over it when
+		 * building dependencies (just like we jump over
+		 * trylock entries):
+		 */
+		if (ret == 2)
+			hlock->read = 2;
+		/*
+		 * Add dependency only if this lock is not the head
+		 * of the chain, and if it's not a secondary read-lock:
+		 */
+		if (!chain_head && ret != 2)
+			if (!check_prevs_add(curr, hlock))
+				return 0;
+		graph_unlock();
+	} else
+		/* after lookup_chain_cache(): */
+		if (unlikely(!debug_locks))
+			return 0;
+
+	return 1;
+}
+#else
+static inline int validate_chain(struct task_struct *curr,
+	       	struct lockdep_map *lock, struct held_lock *hlock,
+		int chain_head, u64 chain_key)
+{
+	return 1;
+}
+#endif
+
+/*
+ * We are building curr_chain_key incrementally, so double-check
+ * it from scratch, to make sure that it's done correctly:
+ */
+static void check_chain_key(struct task_struct *curr)
+{
+#ifdef CONFIG_DEBUG_LOCKDEP
+	struct held_lock *hlock, *prev_hlock = NULL;
+	unsigned int i, id;
+	u64 chain_key = 0;
+
+	for (i = 0; i < curr->lockdep_depth; i++) {
+		hlock = curr->held_locks + i;
+		if (chain_key != hlock->prev_chain_key) {
+			debug_locks_off();
+			printk("hm#1, depth: %u [%u], %016Lx != %016Lx\n",
+				curr->lockdep_depth, i,
+				(unsigned long long)chain_key,
+				(unsigned long long)hlock->prev_chain_key);
+			WARN_ON(1);
+			return;
+		}
+		id = hlock->class - lock_classes;
+		if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
+			return;
+
+		if (prev_hlock && (prev_hlock->irq_context !=
+							hlock->irq_context))
+			chain_key = 0;
+		chain_key = iterate_chain_key(chain_key, id);
+		prev_hlock = hlock;
+	}
+	if (chain_key != curr->curr_chain_key) {
+		debug_locks_off();
+		printk("hm#2, depth: %u [%u], %016Lx != %016Lx\n",
+			curr->lockdep_depth, i,
+			(unsigned long long)chain_key,
+			(unsigned long long)curr->curr_chain_key);
+		WARN_ON(1);
+	}
+#endif
+}
+
+static int
+print_usage_bug(struct task_struct *curr, struct held_lock *this,
+		enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
+{
+	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+		return 0;
+
+	printk("\n=================================\n");
+	printk(  "[ INFO: inconsistent lock state ]\n");
+	print_kernel_version();
+	printk(  "---------------------------------\n");
+
+	printk("inconsistent {%s} -> {%s} usage.\n",
+		usage_str[prev_bit], usage_str[new_bit]);
+
+	printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
+		curr->comm, task_pid_nr(curr),
+		trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT,
+		trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
+		trace_hardirqs_enabled(curr),
+		trace_softirqs_enabled(curr));
+	print_lock(this);
+
+	printk("{%s} state was registered at:\n", usage_str[prev_bit]);
+	print_stack_trace(this->class->usage_traces + prev_bit, 1);
+
+	print_irqtrace_events(curr);
+	printk("\nother info that might help us debug this:\n");
+	lockdep_print_held_locks(curr);
+
+	printk("\nstack backtrace:\n");
+	dump_stack();
+
+	return 0;
+}
+
+/*
+ * Print out an error if an invalid bit is set:
+ */
+static inline int
+valid_state(struct task_struct *curr, struct held_lock *this,
+	    enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
+{
+	if (unlikely(this->class->usage_mask & (1 << bad_bit)))
+		return print_usage_bug(curr, this, bad_bit, new_bit);
+	return 1;
+}
+
+static int mark_lock(struct task_struct *curr, struct held_lock *this,
+		     enum lock_usage_bit new_bit);
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+
+/*
+ * print irq inversion bug:
+ */
+static int
+print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other,
+			struct held_lock *this, int forwards,
+			const char *irqclass)
+{
+	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
+		return 0;
+
+	printk("\n=========================================================\n");
+	printk(  "[ INFO: possible irq lock inversion dependency detected ]\n");
+	print_kernel_version();
+	printk(  "---------------------------------------------------------\n");
+	printk("%s/%d just changed the state of lock:\n",
+		curr->comm, task_pid_nr(curr));
+	print_lock(this);
+	if (forwards)
+		printk("but this lock took another, %s-irq-unsafe lock in the past:\n", irqclass);
+	else
+		printk("but this lock was taken by another, %s-irq-safe lock in the past:\n", irqclass);
+	print_lock_name(other);
+	printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");
+
+	printk("\nother info that might help us debug this:\n");
+	lockdep_print_held_locks(curr);
+
+	printk("\nthe first lock's dependencies:\n");
+	print_lock_dependencies(this->class, 0);
+
+	printk("\nthe second lock's dependencies:\n");
+	print_lock_dependencies(other, 0);
+
+	printk("\nstack backtrace:\n");
+	dump_stack();
+
+	return 0;
+}
+
+/*
+ * Prove that in the forwards-direction subgraph starting at <this>
+ * there is no lock matching <mask>:
+ */
+static int
+check_usage_forwards(struct task_struct *curr, struct held_lock *this,
+		     enum lock_usage_bit bit, const char *irqclass)
+{
+	int ret;
+
+	find_usage_bit = bit;
+	/* fills in <forwards_match> */
+	ret = find_usage_forwards(this->class, 0);
+	if (!ret || ret == 1)
+		return ret;
+
+	return print_irq_inversion_bug(curr, forwards_match, this, 1, irqclass);
+}
+
+/*
+ * Prove that in the backwards-direction subgraph starting at <this>
+ * there is no lock matching <mask>:
+ */
+static int
+check_usage_backwards(struct task_struct *curr, struct held_lock *this,
+		      enum lock_usage_bit bit, const char *irqclass)
+{
+	int ret;
+
+	find_usage_bit = bit;
+	/* fills in <backwards_match> */
+	ret = find_usage_backwards(this->class, 0);
+	if (!ret || ret == 1)
+		return ret;
+
+	return print_irq_inversion_bug(curr, backwards_match, this, 0, irqclass);
+}
+
+void print_irqtrace_events(struct task_struct *curr)
+{
+	printk("irq event stamp: %u\n", curr->irq_events);
+	printk("hardirqs last  enabled at (%u): ", curr->hardirq_enable_event);
+	print_ip_sym(curr->hardirq_enable_ip);
+	printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event);
+	print_ip_sym(curr->hardirq_disable_ip);
+	printk("softirqs last  enabled at (%u): ", curr->softirq_enable_event);
+	print_ip_sym(curr->softirq_enable_ip);
+	printk("softirqs last disabled at (%u): ", curr->softirq_disable_event);
+	print_ip_sym(curr->softirq_disable_ip);
+}
+
+static int hardirq_verbose(struct lock_class *class)
+{
+#if HARDIRQ_VERBOSE
+	return class_filter(class);
+#endif
+	return 0;
+}
+
+static int softirq_verbose(struct lock_class *class)
+{
+#if SOFTIRQ_VERBOSE
+	return class_filter(class);
+#endif
+	return 0;
+}
+
+#define STRICT_READ_CHECKS	1
+
+static int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
+		enum lock_usage_bit new_bit)
+{
+	int ret = 1;
+
+	switch(new_bit) {
+	case LOCK_USED_IN_HARDIRQ:
+		if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS))
+			return 0;
+		if (!valid_state(curr, this, new_bit,
+				 LOCK_ENABLED_HARDIRQS_READ))
+			return 0;
+		/*
+		 * just marked it hardirq-safe, check that this lock
+		 * took no hardirq-unsafe lock in the past:
+		 */
+		if (!check_usage_forwards(curr, this,
+					  LOCK_ENABLED_HARDIRQS, "hard"))
+			return 0;
+#if STRICT_READ_CHECKS
+		/*
+		 * just marked it hardirq-safe, check that this lock
+		 * took no hardirq-unsafe-read lock in the past:
+		 */
+		if (!check_usage_forwards(curr, this,
+				LOCK_ENABLED_HARDIRQS_READ, "hard-read"))
+			return 0;
+#endif
+		if (hardirq_verbose(this->class))
+			ret = 2;
+		break;
+	case LOCK_USED_IN_SOFTIRQ:
+		if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS))
+			return 0;
+		if (!valid_state(curr, this, new_bit,
+				 LOCK_ENABLED_SOFTIRQS_READ))
+			return 0;
+		/*
+		 * just marked it softirq-safe, check that this lock
+		 * took no softirq-unsafe lock in the past:
+		 */
+		if (!check_usage_forwards(curr, this,
+					  LOCK_ENABLED_SOFTIRQS, "soft"))
+			return 0;
+#if STRICT_READ_CHECKS
+		/*
+		 * just marked it softirq-safe, check that this lock
+		 * took no softirq-unsafe-read lock in the past:
+		 */
+		if (!check_usage_forwards(curr, this,
+				LOCK_ENABLED_SOFTIRQS_READ, "soft-read"))
+			return 0;
+#endif
+		if (softirq_verbose(this->class))
+			ret = 2;
+		break;
+	case LOCK_USED_IN_HARDIRQ_READ:
+		if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS))
+			return 0;
+		/*
+		 * just marked it hardirq-read-safe, check that this lock
+		 * took no hardirq-unsafe lock in the past:
+		 */
+		if (!check_usage_forwards(curr, this,
+					  LOCK_ENABLED_HARDIRQS, "hard"))
+			return 0;
+		if (hardirq_verbose(this->class))
+			ret = 2;
+		break;
+	case LOCK_USED_IN_SOFTIRQ_READ:
+		if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS))
+			return 0;
+		/*
+		 * just marked it softirq-read-safe, check that this lock
+		 * took no softirq-unsafe lock in the past:
+		 */
+		if (!check_usage_forwards(curr, this,
+					  LOCK_ENABLED_SOFTIRQS, "soft"))
+			return 0;
+		if (softirq_verbose(this->class))
+			ret = 2;
+		break;
+	case LOCK_ENABLED_HARDIRQS:
+		if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ))
+			return 0;
+		if (!valid_state(curr, this, new_bit,
+				 LOCK_USED_IN_HARDIRQ_READ))
+			return 0;
+		/*
+		 * just marked it hardirq-unsafe, check that no hardirq-safe
+		 * lock in the system ever took it in the past:
+		 */
+		if (!check_usage_backwards(curr, this,
+					   LOCK_USED_IN_HARDIRQ, "hard"))
+			return 0;
+#if STRICT_READ_CHECKS
+		/*
+		 * just marked it hardirq-unsafe, check that no
+		 * hardirq-safe-read lock in the system ever took
+		 * it in the past:
+		 */
+		if (!check_usage_backwards(curr, this,
+				   LOCK_USED_IN_HARDIRQ_READ, "hard-read"))
+			return 0;
+#endif
+		if (hardirq_verbose(this->class))
+			ret = 2;
+		break;
+	case LOCK_ENABLED_SOFTIRQS:
+		if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ))
+			return 0;
+		if (!valid_state(curr, this, new_bit,
+				 LOCK_USED_IN_SOFTIRQ_READ))
+			return 0;
+		/*
+		 * just marked it softirq-unsafe, check that no softirq-safe
+		 * lock in the system ever took it in the past:
+		 */
+		if (!check_usage_backwards(curr, this,
+					   LOCK_USED_IN_SOFTIRQ, "soft"))
+			return 0;
+#if STRICT_READ_CHECKS
+		/*
+		 * just marked it softirq-unsafe, check that no
+		 * softirq-safe-read lock in the system ever took
+		 * it in the past:
+		 */
+		if (!check_usage_backwards(curr, this,
+				   LOCK_USED_IN_SOFTIRQ_READ, "soft-read"))
+			return 0;
+#endif
+		if (softirq_verbose(this->class))
+			ret = 2;
+		break;
+	case LOCK_ENABLED_HARDIRQS_READ:
+		if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ))
+			return 0;
+#if STRICT_READ_CHECKS
+		/*
+		 * just marked it hardirq-read-unsafe, check that no
+		 * hardirq-safe lock in the system ever took it in the past:
+		 */
+		if (!check_usage_backwards(curr, this,
+					   LOCK_USED_IN_HARDIRQ, "hard"))
+			return 0;
+#endif
+		if (hardirq_verbose(this->class))
+			ret = 2;
+		break;
+	case LOCK_ENABLED_SOFTIRQS_READ:
+		if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ))
+			return 0;
+#if STRICT_READ_CHECKS
+		/*
+		 * just marked it softirq-read-unsafe, check that no
+		 * softirq-safe lock in the system ever took it in the past:
+		 */
+		if (!check_usage_backwards(curr, this,
+					   LOCK_USED_IN_SOFTIRQ, "soft"))
+			return 0;
+#endif
+		if (softirq_verbose(this->class))
+			ret = 2;
+		break;
+	default:
+		WARN_ON(1);
+		break;
+	}
+
+	return ret;
+}
+
+/*
+ * Mark all held locks with a usage bit:
+ */
+static int
+mark_held_locks(struct task_struct *curr, int hardirq)
+{
+	enum lock_usage_bit usage_bit;
+	struct held_lock *hlock;
+	int i;
+
+	for (i = 0; i < curr->lockdep_depth; i++) {
+		hlock = curr->held_locks + i;
+
+		if (hardirq) {
+			if (hlock->read)
+				usage_bit = LOCK_ENABLED_HARDIRQS_READ;
+			else
+				usage_bit = LOCK_ENABLED_HARDIRQS;
+		} else {
+			if (hlock->read)
+				usage_bit = LOCK_ENABLED_SOFTIRQS_READ;
+			else
+				usage_bit = LOCK_ENABLED_SOFTIRQS;
+		}
+		if (!mark_lock(curr, hlock, usage_bit))
+			return 0;
+	}
+
+	return 1;
+}
+
+/*
+ * Debugging helper: via this flag we know that we are in
+ * 'early bootup code', and will warn about any invalid irqs-on event:
+ */
+static int early_boot_irqs_enabled;
+
+void early_boot_irqs_off(void)
+{
+	early_boot_irqs_enabled = 0;
+}
+
+void early_boot_irqs_on(void)
+{
+	early_boot_irqs_enabled = 1;
+}
+
+/*
+ * Hardirqs will be enabled:
+ */
+void trace_hardirqs_on(void)
+{
+	struct task_struct *curr = current;
+	unsigned long ip;
+
+	if (unlikely(!debug_locks || current->lockdep_recursion))
+		return;
+
+	if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled)))
+		return;
+
+	if (unlikely(curr->hardirqs_enabled)) {
+		debug_atomic_inc(&redundant_hardirqs_on);
+		return;
+	}
+	/* we'll do an OFF -> ON transition: */
+	curr->hardirqs_enabled = 1;
+	ip = (unsigned long) __builtin_return_address(0);
+
+	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+		return;
+	if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
+		return;
+	/*
+	 * We are going to turn hardirqs on, so set the
+	 * usage bit for all held locks:
+	 */
+	if (!mark_held_locks(curr, 1))
+		return;
+	/*
+	 * If we have softirqs enabled, then set the usage
+	 * bit for all held locks. (disabled hardirqs prevented
+	 * this bit from being set before)
+	 */
+	if (curr->softirqs_enabled)
+		if (!mark_held_locks(curr, 0))
+			return;
+
+	curr->hardirq_enable_ip = ip;
+	curr->hardirq_enable_event = ++curr->irq_events;
+	debug_atomic_inc(&hardirqs_on_events);
+}
+
+EXPORT_SYMBOL(trace_hardirqs_on);
+
+/*
+ * Hardirqs were disabled:
+ */
+void trace_hardirqs_off(void)
+{
+	struct task_struct *curr = current;
+
+	if (unlikely(!debug_locks || current->lockdep_recursion))
+		return;
+
+	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+		return;
+
+	if (curr->hardirqs_enabled) {
+		/*
+		 * We have done an ON -> OFF transition:
+		 */
+		curr->hardirqs_enabled = 0;
+		curr->hardirq_disable_ip = _RET_IP_;
+		curr->hardirq_disable_event = ++curr->irq_events;
+		debug_atomic_inc(&hardirqs_off_events);
+	} else
+		debug_atomic_inc(&redundant_hardirqs_off);
+}
+
+EXPORT_SYMBOL(trace_hardirqs_off);
+
+/*
+ * Softirqs will be enabled:
+ */
+void trace_softirqs_on(unsigned long ip)
+{
+	struct task_struct *curr = current;
+
+	if (unlikely(!debug_locks))
+		return;
+
+	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+		return;
+
+	if (curr->softirqs_enabled) {
+		debug_atomic_inc(&redundant_softirqs_on);
+		return;
+	}
+
+	/*
+	 * We'll do an OFF -> ON transition:
+	 */
+	curr->softirqs_enabled = 1;
+	curr->softirq_enable_ip = ip;
+	curr->softirq_enable_event = ++curr->irq_events;
+	debug_atomic_inc(&softirqs_on_events);
+	/*
+	 * We are going to turn softirqs on, so set the
+	 * usage bit for all held locks, if hardirqs are
+	 * enabled too:
+	 */
+	if (curr->hardirqs_enabled)
+		mark_held_locks(curr, 0);
+}
+
+/*
+ * Softirqs were disabled:
+ */
+void trace_softirqs_off(unsigned long ip)
+{
+	struct task_struct *curr = current;
+
+	if (unlikely(!debug_locks))
+		return;
+
+	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+		return;
+
+	if (curr->softirqs_enabled) {
+		/*
+		 * We have done an ON -> OFF transition:
+		 */
+		curr->softirqs_enabled = 0;
+		curr->softirq_disable_ip = ip;
+		curr->softirq_disable_event = ++curr->irq_events;
+		debug_atomic_inc(&softirqs_off_events);
+		DEBUG_LOCKS_WARN_ON(!softirq_count());
+	} else
+		debug_atomic_inc(&redundant_softirqs_off);
+}
+
+static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
+{
+	/*
+	 * If non-trylock use in a hardirq or softirq context, then
+	 * mark the lock as used in these contexts:
+	 */
+	if (!hlock->trylock) {
+		if (hlock->read) {
+			if (curr->hardirq_context)
+				if (!mark_lock(curr, hlock,
+						LOCK_USED_IN_HARDIRQ_READ))
+					return 0;
+			if (curr->softirq_context)
+				if (!mark_lock(curr, hlock,
+						LOCK_USED_IN_SOFTIRQ_READ))
+					return 0;
+		} else {
+			if (curr->hardirq_context)
+				if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
+					return 0;
+			if (curr->softirq_context)
+				if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ))
+					return 0;
+		}
+	}
+	if (!hlock->hardirqs_off) {
+		if (hlock->read) {
+			if (!mark_lock(curr, hlock,
+					LOCK_ENABLED_HARDIRQS_READ))
+				return 0;
+			if (curr->softirqs_enabled)
+				if (!mark_lock(curr, hlock,
+						LOCK_ENABLED_SOFTIRQS_READ))
+					return 0;
+		} else {
+			if (!mark_lock(curr, hlock,
+					LOCK_ENABLED_HARDIRQS))
+				return 0;
+			if (curr->softirqs_enabled)
+				if (!mark_lock(curr, hlock,
+						LOCK_ENABLED_SOFTIRQS))
+					return 0;
+		}
+	}
+
+	return 1;
+}
+
+static int separate_irq_context(struct task_struct *curr,
+		struct held_lock *hlock)
+{
+	unsigned int depth = curr->lockdep_depth;
+
+	/*
+	 * Keep track of points where we cross into an interrupt context:
+	 */
+	hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) +
+				curr->softirq_context;
+	if (depth) {
+		struct held_lock *prev_hlock;
+
+		prev_hlock = curr->held_locks + depth-1;
+		/*
+		 * If we cross into another context, reset the
+		 * hash key (this also prevents the checking and the
+		 * adding of the dependency to 'prev'):
+		 */
+		if (prev_hlock->irq_context != hlock->irq_context)
+			return 1;
+	}
+	return 0;
+}
+
+#else
+
+static inline
+int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
+		enum lock_usage_bit new_bit)
+{
+	WARN_ON(1);
+	return 1;
+}
+
+static inline int mark_irqflags(struct task_struct *curr,
+		struct held_lock *hlock)
+{
+	return 1;
+}
+
+static inline int separate_irq_context(struct task_struct *curr,
+		struct held_lock *hlock)
+{
+	return 0;
+}
+
+#endif
+
+/*
+ * Mark a lock with a usage bit, and validate the state transition:
+ */
+static int mark_lock(struct task_struct *curr, struct held_lock *this,
+		     enum lock_usage_bit new_bit)
+{
+	unsigned int new_mask = 1 << new_bit, ret = 1;
+
+	/*
+	 * If already set then do not dirty the cacheline,
+	 * nor do any checks:
+	 */
+	if (likely(this->class->usage_mask & new_mask))
+		return 1;
+
+	if (!graph_lock())
+		return 0;
+	/*
+	 * Make sure we didnt race:
+	 */
+	if (unlikely(this->class->usage_mask & new_mask)) {
+		graph_unlock();
+		return 1;
+	}
+
+	this->class->usage_mask |= new_mask;
+
+	if (!save_trace(this->class->usage_traces + new_bit))
+		return 0;
+
+	switch (new_bit) {
+	case LOCK_USED_IN_HARDIRQ:
+	case LOCK_USED_IN_SOFTIRQ:
+	case LOCK_USED_IN_HARDIRQ_READ:
+	case LOCK_USED_IN_SOFTIRQ_READ:
+	case LOCK_ENABLED_HARDIRQS:
+	case LOCK_ENABLED_SOFTIRQS:
+	case LOCK_ENABLED_HARDIRQS_READ:
+	case LOCK_ENABLED_SOFTIRQS_READ:
+		ret = mark_lock_irq(curr, this, new_bit);
+		if (!ret)
+			return 0;
+		break;
+	case LOCK_USED:
+		/*
+		 * Add it to the global list of classes:
+		 */
+		list_add_tail_rcu(&this->class->lock_entry, &all_lock_classes);
+		debug_atomic_dec(&nr_unused_locks);
+		break;
+	default:
+		if (!debug_locks_off_graph_unlock())
+			return 0;
+		WARN_ON(1);
+		return 0;
+	}
+
+	graph_unlock();
+
+	/*
+	 * We must printk outside of the graph_lock:
+	 */
+	if (ret == 2) {
+		printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
+		print_lock(this);
+		print_irqtrace_events(curr);
+		dump_stack();
+	}
+
+	return ret;
+}
+
+/*
+ * Initialize a lock instance's lock-class mapping info:
+ */
+void lockdep_init_map(struct lockdep_map *lock, const char *name,
+		      struct lock_class_key *key, int subclass)
+{
+	if (unlikely(!debug_locks))
+		return;
+
+	if (DEBUG_LOCKS_WARN_ON(!key))
+		return;
+	if (DEBUG_LOCKS_WARN_ON(!name))
+		return;
+	/*
+	 * Sanity check, the lock-class key must be persistent:
+	 */
+	if (!static_obj(key)) {
+		printk("BUG: key %p not in .data!\n", key);
+		DEBUG_LOCKS_WARN_ON(1);
+		return;
+	}
+	lock->name = name;
+	lock->key = key;
+	lock->class_cache = NULL;
+#ifdef CONFIG_LOCK_STAT
+	lock->cpu = raw_smp_processor_id();
+#endif
+	if (subclass)
+		register_lock_class(lock, subclass, 1);
+}
+
+EXPORT_SYMBOL_GPL(lockdep_init_map);
+
+/*
+ * This gets called for every mutex_lock*()/spin_lock*() operation.
+ * We maintain the dependency maps and validate the locking attempt:
+ */
+static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
+			  int trylock, int read, int check, int hardirqs_off,
+			  unsigned long ip)
+{
+	struct task_struct *curr = current;
+	struct lock_class *class = NULL;
+	struct held_lock *hlock;
+	unsigned int depth, id;
+	int chain_head = 0;
+	u64 chain_key;
+
+	if (!prove_locking)
+		check = 1;
+
+	if (unlikely(!debug_locks))
+		return 0;
+
+	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+		return 0;
+
+	if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
+		debug_locks_off();
+		printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n");
+		printk("turning off the locking correctness validator.\n");
+		return 0;
+	}
+
+	if (!subclass)
+		class = lock->class_cache;
+	/*
+	 * Not cached yet or subclass?
+	 */
+	if (unlikely(!class)) {
+		class = register_lock_class(lock, subclass, 0);
+		if (!class)
+			return 0;
+	}
+	debug_atomic_inc((atomic_t *)&class->ops);
+	if (very_verbose(class)) {
+		printk("\nacquire class [%p] %s", class->key, class->name);
+		if (class->name_version > 1)
+			printk("#%d", class->name_version);
+		printk("\n");
+		dump_stack();
+	}
+
+	/*
+	 * Add the lock to the list of currently held locks.
+	 * (we dont increase the depth just yet, up until the
+	 * dependency checks are done)
+	 */
+	depth = curr->lockdep_depth;
+	if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH))
+		return 0;
+
+	hlock = curr->held_locks + depth;
+
+	hlock->class = class;
+	hlock->acquire_ip = ip;
+	hlock->instance = lock;
+	hlock->trylock = trylock;
+	hlock->read = read;
+	hlock->check = check;
+	hlock->hardirqs_off = hardirqs_off;
+#ifdef CONFIG_LOCK_STAT
+	hlock->waittime_stamp = 0;
+	hlock->holdtime_stamp = sched_clock();
+#endif
+
+	if (check == 2 && !mark_irqflags(curr, hlock))
+		return 0;
+
+	/* mark it as used: */
+	if (!mark_lock(curr, hlock, LOCK_USED))
+		return 0;
+
+	/*
+	 * Calculate the chain hash: it's the combined has of all the
+	 * lock keys along the dependency chain. We save the hash value
+	 * at every step so that we can get the current hash easily
+	 * after unlock. The chain hash is then used to cache dependency
+	 * results.
+	 *
+	 * The 'key ID' is what is the most compact key value to drive
+	 * the hash, not class->key.
+	 */
+	id = class - lock_classes;
+	if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
+		return 0;
+
+	chain_key = curr->curr_chain_key;
+	if (!depth) {
+		if (DEBUG_LOCKS_WARN_ON(chain_key != 0))
+			return 0;
+		chain_head = 1;
+	}
+
+	hlock->prev_chain_key = chain_key;
+	if (separate_irq_context(curr, hlock)) {
+		chain_key = 0;
+		chain_head = 1;
+	}
+	chain_key = iterate_chain_key(chain_key, id);
+
+	if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
+		return 0;
+
+	curr->curr_chain_key = chain_key;
+	curr->lockdep_depth++;
+	check_chain_key(curr);
+#ifdef CONFIG_DEBUG_LOCKDEP
+	if (unlikely(!debug_locks))
+		return 0;
+#endif
+	if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
+		debug_locks_off();
+		printk("BUG: MAX_LOCK_DEPTH too low!\n");
+		printk("turning off the locking correctness validator.\n");
+		return 0;
+	}
+
+	if (unlikely(curr->lockdep_depth > max_lockdep_depth))
+		max_lockdep_depth = curr->lockdep_depth;
+
+	return 1;
+}
+
+static int
+print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock,
+			   unsigned long ip)
+{
+	if (!debug_locks_off())
+		return 0;
+	if (debug_locks_silent)
+		return 0;
+
+	printk("\n=====================================\n");
+	printk(  "[ BUG: bad unlock balance detected! ]\n");
+	printk(  "-------------------------------------\n");
+	printk("%s/%d is trying to release lock (",
+		curr->comm, task_pid_nr(curr));
+	print_lockdep_cache(lock);
+	printk(") at:\n");
+	print_ip_sym(ip);
+	printk("but there are no more locks to release!\n");
+	printk("\nother info that might help us debug this:\n");
+	lockdep_print_held_locks(curr);
+
+	printk("\nstack backtrace:\n");
+	dump_stack();
+
+	return 0;
+}
+
+/*
+ * Common debugging checks for both nested and non-nested unlock:
+ */
+static int check_unlock(struct task_struct *curr, struct lockdep_map *lock,
+			unsigned long ip)
+{
+	if (unlikely(!debug_locks))
+		return 0;
+	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
+		return 0;
+
+	if (curr->lockdep_depth <= 0)
+		return print_unlock_inbalance_bug(curr, lock, ip);
+
+	return 1;
+}
+
+/*
+ * Remove the lock to the list of currently held locks in a
+ * potentially non-nested (out of order) manner. This is a
+ * relatively rare operation, as all the unlock APIs default
+ * to nested mode (which uses lock_release()):
+ */
+static int
+lock_release_non_nested(struct task_struct *curr,
+			struct lockdep_map *lock, unsigned long ip)
+{
+	struct held_lock *hlock, *prev_hlock;
+	unsigned int depth;
+	int i;
+
+	/*
+	 * Check whether the lock exists in the current stack
+	 * of held locks:
+	 */
+	depth = curr->lockdep_depth;
+	if (DEBUG_LOCKS_WARN_ON(!depth))
+		return 0;
+
+	prev_hlock = NULL;
+	for (i = depth-1; i >= 0; i--) {
+		hlock = curr->held_locks + i;
+		/*
+		 * We must not cross into another context:
+		 */
+		if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
+			break;
+		if (hlock->instance == lock)
+			goto found_it;
+		prev_hlock = hlock;
+	}
+	return print_unlock_inbalance_bug(curr, lock, ip);
+
+found_it:
+	lock_release_holdtime(hlock);
+
+	/*
+	 * We have the right lock to unlock, 'hlock' points to it.
+	 * Now we remove it from the stack, and add back the other
+	 * entries (if any), recalculating the hash along the way:
+	 */
+	curr->lockdep_depth = i;
+	curr->curr_chain_key = hlock->prev_chain_key;
+
+	for (i++; i < depth; i++) {
+		hlock = curr->held_locks + i;
+		if (!__lock_acquire(hlock->instance,
+			hlock->class->subclass, hlock->trylock,
+				hlock->read, hlock->check, hlock->hardirqs_off,
+				hlock->acquire_ip))
+			return 0;
+	}
+
+	if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1))
+		return 0;
+	return 1;
+}
+
+/*
+ * Remove the lock to the list of currently held locks - this gets
+ * called on mutex_unlock()/spin_unlock*() (or on a failed
+ * mutex_lock_interruptible()). This is done for unlocks that nest
+ * perfectly. (i.e. the current top of the lock-stack is unlocked)
+ */
+static int lock_release_nested(struct task_struct *curr,
+			       struct lockdep_map *lock, unsigned long ip)
+{
+	struct held_lock *hlock;
+	unsigned int depth;
+
+	/*
+	 * Pop off the top of the lock stack:
+	 */
+	depth = curr->lockdep_depth - 1;
+	hlock = curr->held_locks + depth;
+
+	/*
+	 * Is the unlock non-nested:
+	 */
+	if (hlock->instance != lock)
+		return lock_release_non_nested(curr, lock, ip);
+	curr->lockdep_depth--;
+
+	if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0)))
+		return 0;
+
+	curr->curr_chain_key = hlock->prev_chain_key;
+
+	lock_release_holdtime(hlock);
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+	hlock->prev_chain_key = 0;
+	hlock->class = NULL;
+	hlock->acquire_ip = 0;
+	hlock->irq_context = 0;
+#endif
+	return 1;
+}
+
+/*
+ * Remove the lock to the list of currently held locks - this gets
+ * called on mutex_unlock()/spin_unlock*() (or on a failed
+ * mutex_lock_interruptible()). This is done for unlocks that nest
+ * perfectly. (i.e. the current top of the lock-stack is unlocked)
+ */
+static void
+__lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
+{
+	struct task_struct *curr = current;
+
+	if (!check_unlock(curr, lock, ip))
+		return;
+
+	if (nested) {
+		if (!lock_release_nested(curr, lock, ip))
+			return;
+	} else {
+		if (!lock_release_non_nested(curr, lock, ip))
+			return;
+	}
+
+	check_chain_key(curr);
+}
+
+/*
+ * Check whether we follow the irq-flags state precisely:
+ */
+static void check_flags(unsigned long flags)
+{
+#if defined(CONFIG_DEBUG_LOCKDEP) && defined(CONFIG_TRACE_IRQFLAGS)
+	if (!debug_locks)
+		return;
+
+	if (irqs_disabled_flags(flags))
+		DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled);
+	else
+		DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled);
+
+	/*
+	 * We dont accurately track softirq state in e.g.
+	 * hardirq contexts (such as on 4KSTACKS), so only
+	 * check if not in hardirq contexts:
+	 */
+	if (!hardirq_count()) {
+		if (softirq_count())
+			DEBUG_LOCKS_WARN_ON(current->softirqs_enabled);
+		else
+			DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
+	}
+
+	if (!debug_locks)
+		print_irqtrace_events(current);
+#endif
+}
+
+/*
+ * We are not always called with irqs disabled - do that here,
+ * and also avoid lockdep recursion:
+ */
+void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
+		  int trylock, int read, int check, unsigned long ip)
+{
+	unsigned long flags;
+
+	if (unlikely(!lock_stat && !prove_locking))
+		return;
+
+	if (unlikely(current->lockdep_recursion))
+		return;
+
+	raw_local_irq_save(flags);
+	check_flags(flags);
+
+	current->lockdep_recursion = 1;
+	__lock_acquire(lock, subclass, trylock, read, check,
+		       irqs_disabled_flags(flags), ip);
+	current->lockdep_recursion = 0;
+	raw_local_irq_restore(flags);
+}
+
+EXPORT_SYMBOL_GPL(lock_acquire);
+
+void lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
+{
+	unsigned long flags;
+
+	if (unlikely(!lock_stat && !prove_locking))
+		return;
+
+	if (unlikely(current->lockdep_recursion))
+		return;
+
+	raw_local_irq_save(flags);
+	check_flags(flags);
+	current->lockdep_recursion = 1;
+	__lock_release(lock, nested, ip);
+	current->lockdep_recursion = 0;
+	raw_local_irq_restore(flags);
+}
+
+EXPORT_SYMBOL_GPL(lock_release);
+
+#ifdef CONFIG_LOCK_STAT
+static int
+print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,
+			   unsigned long ip)
+{
+	if (!debug_locks_off())
+		return 0;
+	if (debug_locks_silent)
+		return 0;
+
+	printk("\n=================================\n");
+	printk(  "[ BUG: bad contention detected! ]\n");
+	printk(  "---------------------------------\n");
+	printk("%s/%d is trying to contend lock (",
+		curr->comm, task_pid_nr(curr));
+	print_lockdep_cache(lock);
+	printk(") at:\n");
+	print_ip_sym(ip);
+	printk("but there are no locks held!\n");
+	printk("\nother info that might help us debug this:\n");
+	lockdep_print_held_locks(curr);
+
+	printk("\nstack backtrace:\n");
+	dump_stack();
+
+	return 0;
+}
+
+static void
+__lock_contended(struct lockdep_map *lock, unsigned long ip)
+{
+	struct task_struct *curr = current;
+	struct held_lock *hlock, *prev_hlock;
+	struct lock_class_stats *stats;
+	unsigned int depth;
+	int i, point;
+
+	depth = curr->lockdep_depth;
+	if (DEBUG_LOCKS_WARN_ON(!depth))
+		return;
+
+	prev_hlock = NULL;
+	for (i = depth-1; i >= 0; i--) {
+		hlock = curr->held_locks + i;
+		/*
+		 * We must not cross into another context:
+		 */
+		if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
+			break;
+		if (hlock->instance == lock)
+			goto found_it;
+		prev_hlock = hlock;
+	}
+	print_lock_contention_bug(curr, lock, ip);
+	return;
+
+found_it:
+	hlock->waittime_stamp = sched_clock();
+
+	point = lock_contention_point(hlock->class, ip);
+
+	stats = get_lock_stats(hlock->class);
+	if (point < ARRAY_SIZE(stats->contention_point))
+		stats->contention_point[i]++;
+	if (lock->cpu != smp_processor_id())
+		stats->bounces[bounce_contended + !!hlock->read]++;
+	put_lock_stats(stats);
+}
+
+static void
+__lock_acquired(struct lockdep_map *lock)
+{
+	struct task_struct *curr = current;
+	struct held_lock *hlock, *prev_hlock;
+	struct lock_class_stats *stats;
+	unsigned int depth;
+	u64 now;
+	s64 waittime = 0;
+	int i, cpu;
+
+	depth = curr->lockdep_depth;
+	if (DEBUG_LOCKS_WARN_ON(!depth))
+		return;
+
+	prev_hlock = NULL;
+	for (i = depth-1; i >= 0; i--) {
+		hlock = curr->held_locks + i;
+		/*
+		 * We must not cross into another context:
+		 */
+		if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
+			break;
+		if (hlock->instance == lock)
+			goto found_it;
+		prev_hlock = hlock;
+	}
+	print_lock_contention_bug(curr, lock, _RET_IP_);
+	return;
+
+found_it:
+	cpu = smp_processor_id();
+	if (hlock->waittime_stamp) {
+		now = sched_clock();
+		waittime = now - hlock->waittime_stamp;
+		hlock->holdtime_stamp = now;
+	}
+
+	stats = get_lock_stats(hlock->class);
+	if (waittime) {
+		if (hlock->read)
+			lock_time_inc(&stats->read_waittime, waittime);
+		else
+			lock_time_inc(&stats->write_waittime, waittime);
+	}
+	if (lock->cpu != cpu)
+		stats->bounces[bounce_acquired + !!hlock->read]++;
+	put_lock_stats(stats);
+
+	lock->cpu = cpu;
+}
+
+void lock_contended(struct lockdep_map *lock, unsigned long ip)
+{
+	unsigned long flags;
+
+	if (unlikely(!lock_stat))
+		return;
+
+	if (unlikely(current->lockdep_recursion))
+		return;
+
+	raw_local_irq_save(flags);
+	check_flags(flags);
+	current->lockdep_recursion = 1;
+	__lock_contended(lock, ip);
+	current->lockdep_recursion = 0;
+	raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_contended);
+
+void lock_acquired(struct lockdep_map *lock)
+{
+	unsigned long flags;
+
+	if (unlikely(!lock_stat))
+		return;
+
+	if (unlikely(current->lockdep_recursion))
+		return;
+
+	raw_local_irq_save(flags);
+	check_flags(flags);
+	current->lockdep_recursion = 1;
+	__lock_acquired(lock);
+	current->lockdep_recursion = 0;
+	raw_local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(lock_acquired);
+#endif
+
+/*
+ * Used by the testsuite, sanitize the validator state
+ * after a simulated failure:
+ */
+
+void lockdep_reset(void)
+{
+	unsigned long flags;
+	int i;
+
+	raw_local_irq_save(flags);
+	current->curr_chain_key = 0;
+	current->lockdep_depth = 0;
+	current->lockdep_recursion = 0;
+	memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock));
+	nr_hardirq_chains = 0;
+	nr_softirq_chains = 0;
+	nr_process_chains = 0;
+	debug_locks = 1;
+	for (i = 0; i < CHAINHASH_SIZE; i++)
+		INIT_LIST_HEAD(chainhash_table + i);
+	raw_local_irq_restore(flags);
+}
+
+static void zap_class(struct lock_class *class)
+{
+	int i;
+
+	/*
+	 * Remove all dependencies this lock is
+	 * involved in:
+	 */
+	for (i = 0; i < nr_list_entries; i++) {
+		if (list_entries[i].class == class)
+			list_del_rcu(&list_entries[i].entry);
+	}
+	/*
+	 * Unhash the class and remove it from the all_lock_classes list:
+	 */
+	list_del_rcu(&class->hash_entry);
+	list_del_rcu(&class->lock_entry);
+
+}
+
+static inline int within(void *addr, void *start, unsigned long size)
+{
+	return addr >= start && addr < start + size;
+}
+
+void lockdep_free_key_range(void *start, unsigned long size)
+{
+	struct lock_class *class, *next;
+	struct list_head *head;
+	unsigned long flags;
+	int i;
+
+	raw_local_irq_save(flags);
+	graph_lock();
+
+	/*
+	 * Unhash all classes that were created by this module:
+	 */
+	for (i = 0; i < CLASSHASH_SIZE; i++) {
+		head = classhash_table + i;
+		if (list_empty(head))
+			continue;
+		list_for_each_entry_safe(class, next, head, hash_entry)
+			if (within(class->key, start, size))
+				zap_class(class);
+	}
+
+	graph_unlock();
+	raw_local_irq_restore(flags);
+}
+
+void lockdep_reset_lock(struct lockdep_map *lock)
+{
+	struct lock_class *class, *next;
+	struct list_head *head;
+	unsigned long flags;
+	int i, j;
+
+	raw_local_irq_save(flags);
+
+	/*
+	 * Remove all classes this lock might have:
+	 */
+	for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) {
+		/*
+		 * If the class exists we look it up and zap it:
+		 */
+		class = look_up_lock_class(lock, j);
+		if (class)
+			zap_class(class);
+	}
+	/*
+	 * Debug check: in the end all mapped classes should
+	 * be gone.
+	 */
+	graph_lock();
+	for (i = 0; i < CLASSHASH_SIZE; i++) {
+		head = classhash_table + i;
+		if (list_empty(head))
+			continue;
+		list_for_each_entry_safe(class, next, head, hash_entry) {
+			if (unlikely(class == lock->class_cache)) {
+				if (debug_locks_off_graph_unlock())
+					WARN_ON(1);
+				goto out_restore;
+			}
+		}
+	}
+	graph_unlock();
+
+out_restore:
+	raw_local_irq_restore(flags);
+}
+
+void lockdep_init(void)
+{
+	int i;
+
+	/*
+	 * Some architectures have their own start_kernel()
+	 * code which calls lockdep_init(), while we also
+	 * call lockdep_init() from the start_kernel() itself,
+	 * and we want to initialize the hashes only once:
+	 */
+	if (lockdep_initialized)
+		return;
+
+	for (i = 0; i < CLASSHASH_SIZE; i++)
+		INIT_LIST_HEAD(classhash_table + i);
+
+	for (i = 0; i < CHAINHASH_SIZE; i++)
+		INIT_LIST_HEAD(chainhash_table + i);
+
+	lockdep_initialized = 1;
+}
+
+void __init lockdep_info(void)
+{
+	printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
+
+	printk("... MAX_LOCKDEP_SUBCLASSES:    %lu\n", MAX_LOCKDEP_SUBCLASSES);
+	printk("... MAX_LOCK_DEPTH:          %lu\n", MAX_LOCK_DEPTH);
+	printk("... MAX_LOCKDEP_KEYS:        %lu\n", MAX_LOCKDEP_KEYS);
+	printk("... CLASSHASH_SIZE:           %lu\n", CLASSHASH_SIZE);
+	printk("... MAX_LOCKDEP_ENTRIES:     %lu\n", MAX_LOCKDEP_ENTRIES);
+	printk("... MAX_LOCKDEP_CHAINS:      %lu\n", MAX_LOCKDEP_CHAINS);
+	printk("... CHAINHASH_SIZE:          %lu\n", CHAINHASH_SIZE);
+
+	printk(" memory used by lock dependency info: %lu kB\n",
+		(sizeof(struct lock_class) * MAX_LOCKDEP_KEYS +
+		sizeof(struct list_head) * CLASSHASH_SIZE +
+		sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES +
+		sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS +
+		sizeof(struct list_head) * CHAINHASH_SIZE) / 1024);
+
+	printk(" per task-struct memory footprint: %lu bytes\n",
+		sizeof(struct held_lock) * MAX_LOCK_DEPTH);
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+	if (lockdep_init_error) {
+		printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n");
+		printk("Call stack leading to lockdep invocation was:\n");
+		print_stack_trace(&lockdep_init_trace, 0);
+	}
+#endif
+}
+
+static inline int in_range(const void *start, const void *addr, const void *end)
+{
+	return addr >= start && addr <= end;
+}
+
+static void
+print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
+		     const void *mem_to, struct held_lock *hlock)
+{
+	if (!debug_locks_off())
+		return;
+	if (debug_locks_silent)
+		return;
+
+	printk("\n=========================\n");
+	printk(  "[ BUG: held lock freed! ]\n");
+	printk(  "-------------------------\n");
+	printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n",
+		curr->comm, task_pid_nr(curr), mem_from, mem_to-1);
+	print_lock(hlock);
+	lockdep_print_held_locks(curr);
+
+	printk("\nstack backtrace:\n");
+	dump_stack();
+}
+
+/*
+ * Called when kernel memory is freed (or unmapped), or if a lock
+ * is destroyed or reinitialized - this code checks whether there is
+ * any held lock in the memory range of <from> to <to>:
+ */
+void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len)
+{
+	const void *mem_to = mem_from + mem_len, *lock_from, *lock_to;
+	struct task_struct *curr = current;
+	struct held_lock *hlock;
+	unsigned long flags;
+	int i;
+
+	if (unlikely(!debug_locks))
+		return;
+
+	local_irq_save(flags);
+	for (i = 0; i < curr->lockdep_depth; i++) {
+		hlock = curr->held_locks + i;
+
+		lock_from = (void *)hlock->instance;
+		lock_to = (void *)(hlock->instance + 1);
+
+		if (!in_range(mem_from, lock_from, mem_to) &&
+					!in_range(mem_from, lock_to, mem_to))
+			continue;
+
+		print_freed_lock_bug(curr, mem_from, mem_to, hlock);
+		break;
+	}
+	local_irq_restore(flags);
+}
+EXPORT_SYMBOL_GPL(debug_check_no_locks_freed);
+
+static void print_held_locks_bug(struct task_struct *curr)
+{
+	if (!debug_locks_off())
+		return;
+	if (debug_locks_silent)
+		return;
+
+	printk("\n=====================================\n");
+	printk(  "[ BUG: lock held at task exit time! ]\n");
+	printk(  "-------------------------------------\n");
+	printk("%s/%d is exiting with locks still held!\n",
+		curr->comm, task_pid_nr(curr));
+	lockdep_print_held_locks(curr);
+
+	printk("\nstack backtrace:\n");
+	dump_stack();
+}
+
+void debug_check_no_locks_held(struct task_struct *task)
+{
+	if (unlikely(task->lockdep_depth > 0))
+		print_held_locks_bug(task);
+}
+
+void debug_show_all_locks(void)
+{
+	struct task_struct *g, *p;
+	int count = 10;
+	int unlock = 1;
+
+	if (unlikely(!debug_locks)) {
+		printk("INFO: lockdep is turned off.\n");
+		return;
+	}
+	printk("\nShowing all locks held in the system:\n");
+
+	/*
+	 * Here we try to get the tasklist_lock as hard as possible,
+	 * if not successful after 2 seconds we ignore it (but keep
+	 * trying). This is to enable a debug printout even if a
+	 * tasklist_lock-holding task deadlocks or crashes.
+	 */
+retry:
+	if (!read_trylock(&tasklist_lock)) {
+		if (count == 10)
+			printk("hm, tasklist_lock locked, retrying... ");
+		if (count) {
+			count--;
+			printk(" #%d", 10-count);
+			mdelay(200);
+			goto retry;
+		}
+		printk(" ignoring it.\n");
+		unlock = 0;
+	}
+	if (count != 10)
+		printk(" locked it.\n");
+
+	do_each_thread(g, p) {
+		if (p->lockdep_depth)
+			lockdep_print_held_locks(p);
+		if (!unlock)
+			if (read_trylock(&tasklist_lock))
+				unlock = 1;
+	} while_each_thread(g, p);
+
+	printk("\n");
+	printk("=============================================\n\n");
+
+	if (unlock)
+		read_unlock(&tasklist_lock);
+}
+
+EXPORT_SYMBOL_GPL(debug_show_all_locks);
+
+void debug_show_held_locks(struct task_struct *task)
+{
+	if (unlikely(!debug_locks)) {
+		printk("INFO: lockdep is turned off.\n");
+		return;
+	}
+	lockdep_print_held_locks(task);
+}
+
+EXPORT_SYMBOL_GPL(debug_show_held_locks);
+
+void lockdep_sys_exit(void)
+{
+	struct task_struct *curr = current;
+
+	if (unlikely(curr->lockdep_depth)) {
+		if (!debug_locks_off())
+			return;
+		printk("\n================================================\n");
+		printk(  "[ BUG: lock held when returning to user space! ]\n");
+		printk(  "------------------------------------------------\n");
+		printk("%s/%d is leaving the kernel with locks still held!\n",
+				curr->comm, curr->pid);
+		lockdep_print_held_locks(curr);
+	}
+}
Index: linux-2.6-lttng.stable/kernel/lockdep.c
===================================================================
--- linux-2.6-lttng.stable.orig/kernel/lockdep.c	2007-10-29 09:51:06.000000000 -0400
+++ /dev/null	1970-01-01 00:00:00.000000000 +0000
@@ -1,3217 +0,0 @@
-/*
- * kernel/lockdep.c
- *
- * Runtime locking correctness validator
- *
- * Started by Ingo Molnar:
- *
- *  Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@xxxxxxxxxx>
- *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@xxxxxxxxxx>
- *
- * this code maps all the lock dependencies as they occur in a live kernel
- * and will warn about the following classes of locking bugs:
- *
- * - lock inversion scenarios
- * - circular lock dependencies
- * - hardirq/softirq safe/unsafe locking bugs
- *
- * Bugs are reported even if the current locking scenario does not cause
- * any deadlock at this point.
- *
- * I.e. if anytime in the past two locks were taken in a different order,
- * even if it happened for another task, even if those were different
- * locks (but of the same class as this lock), this code will detect it.
- *
- * Thanks to Arjan van de Ven for coming up with the initial idea of
- * mapping lock dependencies runtime.
- */
-#include <linux/mutex.h>
-#include <linux/sched.h>
-#include <linux/delay.h>
-#include <linux/module.h>
-#include <linux/proc_fs.h>
-#include <linux/seq_file.h>
-#include <linux/spinlock.h>
-#include <linux/kallsyms.h>
-#include <linux/interrupt.h>
-#include <linux/stacktrace.h>
-#include <linux/debug_locks.h>
-#include <linux/irqflags.h>
-#include <linux/utsname.h>
-#include <linux/hash.h>
-
-#include <asm/sections.h>
-
-#include "lockdep_internals.h"
-
-#ifdef CONFIG_PROVE_LOCKING
-int prove_locking = 1;
-module_param(prove_locking, int, 0644);
-#else
-#define prove_locking 0
-#endif
-
-#ifdef CONFIG_LOCK_STAT
-int lock_stat = 1;
-module_param(lock_stat, int, 0644);
-#else
-#define lock_stat 0
-#endif
-
-/*
- * lockdep_lock: protects the lockdep graph, the hashes and the
- *               class/list/hash allocators.
- *
- * This is one of the rare exceptions where it's justified
- * to use a raw spinlock - we really dont want the spinlock
- * code to recurse back into the lockdep code...
- */
-static raw_spinlock_t lockdep_lock = (raw_spinlock_t)__RAW_SPIN_LOCK_UNLOCKED;
-
-static int graph_lock(void)
-{
-	__raw_spin_lock(&lockdep_lock);
-	/*
-	 * Make sure that if another CPU detected a bug while
-	 * walking the graph we dont change it (while the other
-	 * CPU is busy printing out stuff with the graph lock
-	 * dropped already)
-	 */
-	if (!debug_locks) {
-		__raw_spin_unlock(&lockdep_lock);
-		return 0;
-	}
-	return 1;
-}
-
-static inline int graph_unlock(void)
-{
-	if (debug_locks && !__raw_spin_is_locked(&lockdep_lock))
-		return DEBUG_LOCKS_WARN_ON(1);
-
-	__raw_spin_unlock(&lockdep_lock);
-	return 0;
-}
-
-/*
- * Turn lock debugging off and return with 0 if it was off already,
- * and also release the graph lock:
- */
-static inline int debug_locks_off_graph_unlock(void)
-{
-	int ret = debug_locks_off();
-
-	__raw_spin_unlock(&lockdep_lock);
-
-	return ret;
-}
-
-static int lockdep_initialized;
-
-unsigned long nr_list_entries;
-static struct lock_list list_entries[MAX_LOCKDEP_ENTRIES];
-
-/*
- * All data structures here are protected by the global debug_lock.
- *
- * Mutex key structs only get allocated, once during bootup, and never
- * get freed - this significantly simplifies the debugging code.
- */
-unsigned long nr_lock_classes;
-static struct lock_class lock_classes[MAX_LOCKDEP_KEYS];
-
-#ifdef CONFIG_LOCK_STAT
-static DEFINE_PER_CPU(struct lock_class_stats[MAX_LOCKDEP_KEYS], lock_stats);
-
-static int lock_contention_point(struct lock_class *class, unsigned long ip)
-{
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) {
-		if (class->contention_point[i] == 0) {
-			class->contention_point[i] = ip;
-			break;
-		}
-		if (class->contention_point[i] == ip)
-			break;
-	}
-
-	return i;
-}
-
-static void lock_time_inc(struct lock_time *lt, s64 time)
-{
-	if (time > lt->max)
-		lt->max = time;
-
-	if (time < lt->min || !lt->min)
-		lt->min = time;
-
-	lt->total += time;
-	lt->nr++;
-}
-
-static inline void lock_time_add(struct lock_time *src, struct lock_time *dst)
-{
-	dst->min += src->min;
-	dst->max += src->max;
-	dst->total += src->total;
-	dst->nr += src->nr;
-}
-
-struct lock_class_stats lock_stats(struct lock_class *class)
-{
-	struct lock_class_stats stats;
-	int cpu, i;
-
-	memset(&stats, 0, sizeof(struct lock_class_stats));
-	for_each_possible_cpu(cpu) {
-		struct lock_class_stats *pcs =
-			&per_cpu(lock_stats, cpu)[class - lock_classes];
-
-		for (i = 0; i < ARRAY_SIZE(stats.contention_point); i++)
-			stats.contention_point[i] += pcs->contention_point[i];
-
-		lock_time_add(&pcs->read_waittime, &stats.read_waittime);
-		lock_time_add(&pcs->write_waittime, &stats.write_waittime);
-
-		lock_time_add(&pcs->read_holdtime, &stats.read_holdtime);
-		lock_time_add(&pcs->write_holdtime, &stats.write_holdtime);
-
-		for (i = 0; i < ARRAY_SIZE(stats.bounces); i++)
-			stats.bounces[i] += pcs->bounces[i];
-	}
-
-	return stats;
-}
-
-void clear_lock_stats(struct lock_class *class)
-{
-	int cpu;
-
-	for_each_possible_cpu(cpu) {
-		struct lock_class_stats *cpu_stats =
-			&per_cpu(lock_stats, cpu)[class - lock_classes];
-
-		memset(cpu_stats, 0, sizeof(struct lock_class_stats));
-	}
-	memset(class->contention_point, 0, sizeof(class->contention_point));
-}
-
-static struct lock_class_stats *get_lock_stats(struct lock_class *class)
-{
-	return &get_cpu_var(lock_stats)[class - lock_classes];
-}
-
-static void put_lock_stats(struct lock_class_stats *stats)
-{
-	put_cpu_var(lock_stats);
-}
-
-static void lock_release_holdtime(struct held_lock *hlock)
-{
-	struct lock_class_stats *stats;
-	s64 holdtime;
-
-	if (!lock_stat)
-		return;
-
-	holdtime = sched_clock() - hlock->holdtime_stamp;
-
-	stats = get_lock_stats(hlock->class);
-	if (hlock->read)
-		lock_time_inc(&stats->read_holdtime, holdtime);
-	else
-		lock_time_inc(&stats->write_holdtime, holdtime);
-	put_lock_stats(stats);
-}
-#else
-static inline void lock_release_holdtime(struct held_lock *hlock)
-{
-}
-#endif
-
-/*
- * We keep a global list of all lock classes. The list only grows,
- * never shrinks. The list is only accessed with the lockdep
- * spinlock lock held.
- */
-LIST_HEAD(all_lock_classes);
-
-/*
- * The lockdep classes are in a hash-table as well, for fast lookup:
- */
-#define CLASSHASH_BITS		(MAX_LOCKDEP_KEYS_BITS - 1)
-#define CLASSHASH_SIZE		(1UL << CLASSHASH_BITS)
-#define __classhashfn(key)	hash_long((unsigned long)key, CLASSHASH_BITS)
-#define classhashentry(key)	(classhash_table + __classhashfn((key)))
-
-static struct list_head classhash_table[CLASSHASH_SIZE];
-
-/*
- * We put the lock dependency chains into a hash-table as well, to cache
- * their existence:
- */
-#define CHAINHASH_BITS		(MAX_LOCKDEP_CHAINS_BITS-1)
-#define CHAINHASH_SIZE		(1UL << CHAINHASH_BITS)
-#define __chainhashfn(chain)	hash_long(chain, CHAINHASH_BITS)
-#define chainhashentry(chain)	(chainhash_table + __chainhashfn((chain)))
-
-static struct list_head chainhash_table[CHAINHASH_SIZE];
-
-/*
- * The hash key of the lock dependency chains is a hash itself too:
- * it's a hash of all locks taken up to that lock, including that lock.
- * It's a 64-bit hash, because it's important for the keys to be
- * unique.
- */
-#define iterate_chain_key(key1, key2) \
-	(((key1) << MAX_LOCKDEP_KEYS_BITS) ^ \
-	((key1) >> (64-MAX_LOCKDEP_KEYS_BITS)) ^ \
-	(key2))
-
-void lockdep_off(void)
-{
-	current->lockdep_recursion++;
-}
-
-EXPORT_SYMBOL(lockdep_off);
-
-void lockdep_on(void)
-{
-	current->lockdep_recursion--;
-}
-
-EXPORT_SYMBOL(lockdep_on);
-
-/*
- * Debugging switches:
- */
-
-#define VERBOSE			0
-#define VERY_VERBOSE		0
-
-#if VERBOSE
-# define HARDIRQ_VERBOSE	1
-# define SOFTIRQ_VERBOSE	1
-#else
-# define HARDIRQ_VERBOSE	0
-# define SOFTIRQ_VERBOSE	0
-#endif
-
-#if VERBOSE || HARDIRQ_VERBOSE || SOFTIRQ_VERBOSE
-/*
- * Quick filtering for interesting events:
- */
-static int class_filter(struct lock_class *class)
-{
-#if 0
-	/* Example */
-	if (class->name_version == 1 &&
-			!strcmp(class->name, "lockname"))
-		return 1;
-	if (class->name_version == 1 &&
-			!strcmp(class->name, "&struct->lockfield"))
-		return 1;
-#endif
-	/* Filter everything else. 1 would be to allow everything else */
-	return 0;
-}
-#endif
-
-static int verbose(struct lock_class *class)
-{
-#if VERBOSE
-	return class_filter(class);
-#endif
-	return 0;
-}
-
-/*
- * Stack-trace: tightly packed array of stack backtrace
- * addresses. Protected by the graph_lock.
- */
-unsigned long nr_stack_trace_entries;
-static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES];
-
-static int save_trace(struct stack_trace *trace)
-{
-	trace->nr_entries = 0;
-	trace->max_entries = MAX_STACK_TRACE_ENTRIES - nr_stack_trace_entries;
-	trace->entries = stack_trace + nr_stack_trace_entries;
-
-	trace->skip = 3;
-
-	save_stack_trace(trace);
-
-	trace->max_entries = trace->nr_entries;
-
-	nr_stack_trace_entries += trace->nr_entries;
-
-	if (nr_stack_trace_entries == MAX_STACK_TRACE_ENTRIES) {
-		if (!debug_locks_off_graph_unlock())
-			return 0;
-
-		printk("BUG: MAX_STACK_TRACE_ENTRIES too low!\n");
-		printk("turning off the locking correctness validator.\n");
-		dump_stack();
-
-		return 0;
-	}
-
-	return 1;
-}
-
-unsigned int nr_hardirq_chains;
-unsigned int nr_softirq_chains;
-unsigned int nr_process_chains;
-unsigned int max_lockdep_depth;
-unsigned int max_recursion_depth;
-
-#ifdef CONFIG_DEBUG_LOCKDEP
-/*
- * We cannot printk in early bootup code. Not even early_printk()
- * might work. So we mark any initialization errors and printk
- * about it later on, in lockdep_info().
- */
-static int lockdep_init_error;
-static unsigned long lockdep_init_trace_data[20];
-static struct stack_trace lockdep_init_trace = {
-	.max_entries = ARRAY_SIZE(lockdep_init_trace_data),
-	.entries = lockdep_init_trace_data,
-};
-
-/*
- * Various lockdep statistics:
- */
-atomic_t chain_lookup_hits;
-atomic_t chain_lookup_misses;
-atomic_t hardirqs_on_events;
-atomic_t hardirqs_off_events;
-atomic_t redundant_hardirqs_on;
-atomic_t redundant_hardirqs_off;
-atomic_t softirqs_on_events;
-atomic_t softirqs_off_events;
-atomic_t redundant_softirqs_on;
-atomic_t redundant_softirqs_off;
-atomic_t nr_unused_locks;
-atomic_t nr_cyclic_checks;
-atomic_t nr_cyclic_check_recursions;
-atomic_t nr_find_usage_forwards_checks;
-atomic_t nr_find_usage_forwards_recursions;
-atomic_t nr_find_usage_backwards_checks;
-atomic_t nr_find_usage_backwards_recursions;
-# define debug_atomic_inc(ptr)		atomic_inc(ptr)
-# define debug_atomic_dec(ptr)		atomic_dec(ptr)
-# define debug_atomic_read(ptr)		atomic_read(ptr)
-#else
-# define debug_atomic_inc(ptr)		do { } while (0)
-# define debug_atomic_dec(ptr)		do { } while (0)
-# define debug_atomic_read(ptr)		0
-#endif
-
-/*
- * Locking printouts:
- */
-
-static const char *usage_str[] =
-{
-	[LOCK_USED] =			"initial-use ",
-	[LOCK_USED_IN_HARDIRQ] =	"in-hardirq-W",
-	[LOCK_USED_IN_SOFTIRQ] =	"in-softirq-W",
-	[LOCK_ENABLED_SOFTIRQS] =	"softirq-on-W",
-	[LOCK_ENABLED_HARDIRQS] =	"hardirq-on-W",
-	[LOCK_USED_IN_HARDIRQ_READ] =	"in-hardirq-R",
-	[LOCK_USED_IN_SOFTIRQ_READ] =	"in-softirq-R",
-	[LOCK_ENABLED_SOFTIRQS_READ] =	"softirq-on-R",
-	[LOCK_ENABLED_HARDIRQS_READ] =	"hardirq-on-R",
-};
-
-const char * __get_key_name(struct lockdep_subclass_key *key, char *str)
-{
-	return kallsyms_lookup((unsigned long)key, NULL, NULL, NULL, str);
-}
-
-void
-get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4)
-{
-	*c1 = '.', *c2 = '.', *c3 = '.', *c4 = '.';
-
-	if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
-		*c1 = '+';
-	else
-		if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
-			*c1 = '-';
-
-	if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
-		*c2 = '+';
-	else
-		if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
-			*c2 = '-';
-
-	if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
-		*c3 = '-';
-	if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ) {
-		*c3 = '+';
-		if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
-			*c3 = '?';
-	}
-
-	if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
-		*c4 = '-';
-	if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ) {
-		*c4 = '+';
-		if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
-			*c4 = '?';
-	}
-}
-
-static void print_lock_name(struct lock_class *class)
-{
-	char str[KSYM_NAME_LEN], c1, c2, c3, c4;
-	const char *name;
-
-	get_usage_chars(class, &c1, &c2, &c3, &c4);
-
-	name = class->name;
-	if (!name) {
-		name = __get_key_name(class->key, str);
-		printk(" (%s", name);
-	} else {
-		printk(" (%s", name);
-		if (class->name_version > 1)
-			printk("#%d", class->name_version);
-		if (class->subclass)
-			printk("/%d", class->subclass);
-	}
-	printk("){%c%c%c%c}", c1, c2, c3, c4);
-}
-
-static void print_lockdep_cache(struct lockdep_map *lock)
-{
-	const char *name;
-	char str[KSYM_NAME_LEN];
-
-	name = lock->name;
-	if (!name)
-		name = __get_key_name(lock->key->subkeys, str);
-
-	printk("%s", name);
-}
-
-static void print_lock(struct held_lock *hlock)
-{
-	print_lock_name(hlock->class);
-	printk(", at: ");
-	print_ip_sym(hlock->acquire_ip);
-}
-
-static void lockdep_print_held_locks(struct task_struct *curr)
-{
-	int i, depth = curr->lockdep_depth;
-
-	if (!depth) {
-		printk("no locks held by %s/%d.\n", curr->comm, task_pid_nr(curr));
-		return;
-	}
-	printk("%d lock%s held by %s/%d:\n",
-		depth, depth > 1 ? "s" : "", curr->comm, task_pid_nr(curr));
-
-	for (i = 0; i < depth; i++) {
-		printk(" #%d: ", i);
-		print_lock(curr->held_locks + i);
-	}
-}
-
-static void print_lock_class_header(struct lock_class *class, int depth)
-{
-	int bit;
-
-	printk("%*s->", depth, "");
-	print_lock_name(class);
-	printk(" ops: %lu", class->ops);
-	printk(" {\n");
-
-	for (bit = 0; bit < LOCK_USAGE_STATES; bit++) {
-		if (class->usage_mask & (1 << bit)) {
-			int len = depth;
-
-			len += printk("%*s   %s", depth, "", usage_str[bit]);
-			len += printk(" at:\n");
-			print_stack_trace(class->usage_traces + bit, len);
-		}
-	}
-	printk("%*s }\n", depth, "");
-
-	printk("%*s ... key      at: ",depth,"");
-	print_ip_sym((unsigned long)class->key);
-}
-
-/*
- * printk all lock dependencies starting at <entry>:
- */
-static void print_lock_dependencies(struct lock_class *class, int depth)
-{
-	struct lock_list *entry;
-
-	if (DEBUG_LOCKS_WARN_ON(depth >= 20))
-		return;
-
-	print_lock_class_header(class, depth);
-
-	list_for_each_entry(entry, &class->locks_after, entry) {
-		if (DEBUG_LOCKS_WARN_ON(!entry->class))
-			return;
-
-		print_lock_dependencies(entry->class, depth + 1);
-
-		printk("%*s ... acquired at:\n",depth,"");
-		print_stack_trace(&entry->trace, 2);
-		printk("\n");
-	}
-}
-
-static void print_kernel_version(void)
-{
-	printk("%s %.*s\n", init_utsname()->release,
-		(int)strcspn(init_utsname()->version, " "),
-		init_utsname()->version);
-}
-
-static int very_verbose(struct lock_class *class)
-{
-#if VERY_VERBOSE
-	return class_filter(class);
-#endif
-	return 0;
-}
-
-/*
- * Is this the address of a static object:
- */
-static int static_obj(void *obj)
-{
-	unsigned long start = (unsigned long) &_stext,
-		      end   = (unsigned long) &_end,
-		      addr  = (unsigned long) obj;
-#ifdef CONFIG_SMP
-	int i;
-#endif
-
-	/*
-	 * static variable?
-	 */
-	if ((addr >= start) && (addr < end))
-		return 1;
-
-#ifdef CONFIG_SMP
-	/*
-	 * percpu var?
-	 */
-	for_each_possible_cpu(i) {
-		start = (unsigned long) &__per_cpu_start + per_cpu_offset(i);
-		end   = (unsigned long) &__per_cpu_start + PERCPU_ENOUGH_ROOM
-					+ per_cpu_offset(i);
-
-		if ((addr >= start) && (addr < end))
-			return 1;
-	}
-#endif
-
-	/*
-	 * module var?
-	 */
-	return is_module_address(addr);
-}
-
-/*
- * To make lock name printouts unique, we calculate a unique
- * class->name_version generation counter:
- */
-static int count_matching_names(struct lock_class *new_class)
-{
-	struct lock_class *class;
-	int count = 0;
-
-	if (!new_class->name)
-		return 0;
-
-	list_for_each_entry(class, &all_lock_classes, lock_entry) {
-		if (new_class->key - new_class->subclass == class->key)
-			return class->name_version;
-		if (class->name && !strcmp(class->name, new_class->name))
-			count = max(count, class->name_version);
-	}
-
-	return count + 1;
-}
-
-/*
- * Register a lock's class in the hash-table, if the class is not present
- * yet. Otherwise we look it up. We cache the result in the lock object
- * itself, so actual lookup of the hash should be once per lock object.
- */
-static inline struct lock_class *
-look_up_lock_class(struct lockdep_map *lock, unsigned int subclass)
-{
-	struct lockdep_subclass_key *key;
-	struct list_head *hash_head;
-	struct lock_class *class;
-
-#ifdef CONFIG_DEBUG_LOCKDEP
-	/*
-	 * If the architecture calls into lockdep before initializing
-	 * the hashes then we'll warn about it later. (we cannot printk
-	 * right now)
-	 */
-	if (unlikely(!lockdep_initialized)) {
-		lockdep_init();
-		lockdep_init_error = 1;
-		save_stack_trace(&lockdep_init_trace);
-	}
-#endif
-
-	/*
-	 * Static locks do not have their class-keys yet - for them the key
-	 * is the lock object itself:
-	 */
-	if (unlikely(!lock->key))
-		lock->key = (void *)lock;
-
-	/*
-	 * NOTE: the class-key must be unique. For dynamic locks, a static
-	 * lock_class_key variable is passed in through the mutex_init()
-	 * (or spin_lock_init()) call - which acts as the key. For static
-	 * locks we use the lock object itself as the key.
-	 */
-	BUILD_BUG_ON(sizeof(struct lock_class_key) >
-			sizeof(struct lockdep_map));
-
-	key = lock->key->subkeys + subclass;
-
-	hash_head = classhashentry(key);
-
-	/*
-	 * We can walk the hash lockfree, because the hash only
-	 * grows, and we are careful when adding entries to the end:
-	 */
-	list_for_each_entry(class, hash_head, hash_entry) {
-		if (class->key == key) {
-			WARN_ON_ONCE(class->name != lock->name);
-			return class;
-		}
-	}
-
-	return NULL;
-}
-
-/*
- * Register a lock's class in the hash-table, if the class is not present
- * yet. Otherwise we look it up. We cache the result in the lock object
- * itself, so actual lookup of the hash should be once per lock object.
- */
-static inline struct lock_class *
-register_lock_class(struct lockdep_map *lock, unsigned int subclass, int force)
-{
-	struct lockdep_subclass_key *key;
-	struct list_head *hash_head;
-	struct lock_class *class;
-	unsigned long flags;
-
-	class = look_up_lock_class(lock, subclass);
-	if (likely(class))
-		return class;
-
-	/*
-	 * Debug-check: all keys must be persistent!
- 	 */
-	if (!static_obj(lock->key)) {
-		debug_locks_off();
-		printk("INFO: trying to register non-static key.\n");
-		printk("the code is fine but needs lockdep annotation.\n");
-		printk("turning off the locking correctness validator.\n");
-		dump_stack();
-
-		return NULL;
-	}
-
-	key = lock->key->subkeys + subclass;
-	hash_head = classhashentry(key);
-
-	raw_local_irq_save(flags);
-	if (!graph_lock()) {
-		raw_local_irq_restore(flags);
-		return NULL;
-	}
-	/*
-	 * We have to do the hash-walk again, to avoid races
-	 * with another CPU:
-	 */
-	list_for_each_entry(class, hash_head, hash_entry)
-		if (class->key == key)
-			goto out_unlock_set;
-	/*
-	 * Allocate a new key from the static array, and add it to
-	 * the hash:
-	 */
-	if (nr_lock_classes >= MAX_LOCKDEP_KEYS) {
-		if (!debug_locks_off_graph_unlock()) {
-			raw_local_irq_restore(flags);
-			return NULL;
-		}
-		raw_local_irq_restore(flags);
-
-		printk("BUG: MAX_LOCKDEP_KEYS too low!\n");
-		printk("turning off the locking correctness validator.\n");
-		return NULL;
-	}
-	class = lock_classes + nr_lock_classes++;
-	debug_atomic_inc(&nr_unused_locks);
-	class->key = key;
-	class->name = lock->name;
-	class->subclass = subclass;
-	INIT_LIST_HEAD(&class->lock_entry);
-	INIT_LIST_HEAD(&class->locks_before);
-	INIT_LIST_HEAD(&class->locks_after);
-	class->name_version = count_matching_names(class);
-	/*
-	 * We use RCU's safe list-add method to make
-	 * parallel walking of the hash-list safe:
-	 */
-	list_add_tail_rcu(&class->hash_entry, hash_head);
-
-	if (verbose(class)) {
-		graph_unlock();
-		raw_local_irq_restore(flags);
-
-		printk("\nnew class %p: %s", class->key, class->name);
-		if (class->name_version > 1)
-			printk("#%d", class->name_version);
-		printk("\n");
-		dump_stack();
-
-		raw_local_irq_save(flags);
-		if (!graph_lock()) {
-			raw_local_irq_restore(flags);
-			return NULL;
-		}
-	}
-out_unlock_set:
-	graph_unlock();
-	raw_local_irq_restore(flags);
-
-	if (!subclass || force)
-		lock->class_cache = class;
-
-	if (DEBUG_LOCKS_WARN_ON(class->subclass != subclass))
-		return NULL;
-
-	return class;
-}
-
-#ifdef CONFIG_PROVE_LOCKING
-/*
- * Allocate a lockdep entry. (assumes the graph_lock held, returns
- * with NULL on failure)
- */
-static struct lock_list *alloc_list_entry(void)
-{
-	if (nr_list_entries >= MAX_LOCKDEP_ENTRIES) {
-		if (!debug_locks_off_graph_unlock())
-			return NULL;
-
-		printk("BUG: MAX_LOCKDEP_ENTRIES too low!\n");
-		printk("turning off the locking correctness validator.\n");
-		return NULL;
-	}
-	return list_entries + nr_list_entries++;
-}
-
-/*
- * Add a new dependency to the head of the list:
- */
-static int add_lock_to_list(struct lock_class *class, struct lock_class *this,
-			    struct list_head *head, unsigned long ip, int distance)
-{
-	struct lock_list *entry;
-	/*
-	 * Lock not present yet - get a new dependency struct and
-	 * add it to the list:
-	 */
-	entry = alloc_list_entry();
-	if (!entry)
-		return 0;
-
-	entry->class = this;
-	entry->distance = distance;
-	if (!save_trace(&entry->trace))
-		return 0;
-
-	/*
-	 * Since we never remove from the dependency list, the list can
-	 * be walked lockless by other CPUs, it's only allocation
-	 * that must be protected by the spinlock. But this also means
-	 * we must make new entries visible only once writes to the
-	 * entry become visible - hence the RCU op:
-	 */
-	list_add_tail_rcu(&entry->entry, head);
-
-	return 1;
-}
-
-/*
- * Recursive, forwards-direction lock-dependency checking, used for
- * both noncyclic checking and for hardirq-unsafe/softirq-unsafe
- * checking.
- *
- * (to keep the stackframe of the recursive functions small we
- *  use these global variables, and we also mark various helper
- *  functions as noinline.)
- */
-static struct held_lock *check_source, *check_target;
-
-/*
- * Print a dependency chain entry (this is only done when a deadlock
- * has been detected):
- */
-static noinline int
-print_circular_bug_entry(struct lock_list *target, unsigned int depth)
-{
-	if (debug_locks_silent)
-		return 0;
-	printk("\n-> #%u", depth);
-	print_lock_name(target->class);
-	printk(":\n");
-	print_stack_trace(&target->trace, 6);
-
-	return 0;
-}
-
-/*
- * When a circular dependency is detected, print the
- * header first:
- */
-static noinline int
-print_circular_bug_header(struct lock_list *entry, unsigned int depth)
-{
-	struct task_struct *curr = current;
-
-	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
-		return 0;
-
-	printk("\n=======================================================\n");
-	printk(  "[ INFO: possible circular locking dependency detected ]\n");
-	print_kernel_version();
-	printk(  "-------------------------------------------------------\n");
-	printk("%s/%d is trying to acquire lock:\n",
-		curr->comm, task_pid_nr(curr));
-	print_lock(check_source);
-	printk("\nbut task is already holding lock:\n");
-	print_lock(check_target);
-	printk("\nwhich lock already depends on the new lock.\n\n");
-	printk("\nthe existing dependency chain (in reverse order) is:\n");
-
-	print_circular_bug_entry(entry, depth);
-
-	return 0;
-}
-
-static noinline int print_circular_bug_tail(void)
-{
-	struct task_struct *curr = current;
-	struct lock_list this;
-
-	if (debug_locks_silent)
-		return 0;
-
-	this.class = check_source->class;
-	if (!save_trace(&this.trace))
-		return 0;
-
-	print_circular_bug_entry(&this, 0);
-
-	printk("\nother info that might help us debug this:\n\n");
-	lockdep_print_held_locks(curr);
-
-	printk("\nstack backtrace:\n");
-	dump_stack();
-
-	return 0;
-}
-
-#define RECURSION_LIMIT 40
-
-static int noinline print_infinite_recursion_bug(void)
-{
-	if (!debug_locks_off_graph_unlock())
-		return 0;
-
-	WARN_ON(1);
-
-	return 0;
-}
-
-/*
- * Prove that the dependency graph starting at <entry> can not
- * lead to <target>. Print an error and return 0 if it does.
- */
-static noinline int
-check_noncircular(struct lock_class *source, unsigned int depth)
-{
-	struct lock_list *entry;
-
-	debug_atomic_inc(&nr_cyclic_check_recursions);
-	if (depth > max_recursion_depth)
-		max_recursion_depth = depth;
-	if (depth >= RECURSION_LIMIT)
-		return print_infinite_recursion_bug();
-	/*
-	 * Check this lock's dependency list:
-	 */
-	list_for_each_entry(entry, &source->locks_after, entry) {
-		if (entry->class == check_target->class)
-			return print_circular_bug_header(entry, depth+1);
-		debug_atomic_inc(&nr_cyclic_checks);
-		if (!check_noncircular(entry->class, depth+1))
-			return print_circular_bug_entry(entry, depth+1);
-	}
-	return 1;
-}
-
-#ifdef CONFIG_TRACE_IRQFLAGS
-/*
- * Forwards and backwards subgraph searching, for the purposes of
- * proving that two subgraphs can be connected by a new dependency
- * without creating any illegal irq-safe -> irq-unsafe lock dependency.
- */
-static enum lock_usage_bit find_usage_bit;
-static struct lock_class *forwards_match, *backwards_match;
-
-/*
- * Find a node in the forwards-direction dependency sub-graph starting
- * at <source> that matches <find_usage_bit>.
- *
- * Return 2 if such a node exists in the subgraph, and put that node
- * into <forwards_match>.
- *
- * Return 1 otherwise and keep <forwards_match> unchanged.
- * Return 0 on error.
- */
-static noinline int
-find_usage_forwards(struct lock_class *source, unsigned int depth)
-{
-	struct lock_list *entry;
-	int ret;
-
-	if (depth > max_recursion_depth)
-		max_recursion_depth = depth;
-	if (depth >= RECURSION_LIMIT)
-		return print_infinite_recursion_bug();
-
-	debug_atomic_inc(&nr_find_usage_forwards_checks);
-	if (source->usage_mask & (1 << find_usage_bit)) {
-		forwards_match = source;
-		return 2;
-	}
-
-	/*
-	 * Check this lock's dependency list:
-	 */
-	list_for_each_entry(entry, &source->locks_after, entry) {
-		debug_atomic_inc(&nr_find_usage_forwards_recursions);
-		ret = find_usage_forwards(entry->class, depth+1);
-		if (ret == 2 || ret == 0)
-			return ret;
-	}
-	return 1;
-}
-
-/*
- * Find a node in the backwards-direction dependency sub-graph starting
- * at <source> that matches <find_usage_bit>.
- *
- * Return 2 if such a node exists in the subgraph, and put that node
- * into <backwards_match>.
- *
- * Return 1 otherwise and keep <backwards_match> unchanged.
- * Return 0 on error.
- */
-static noinline int
-find_usage_backwards(struct lock_class *source, unsigned int depth)
-{
-	struct lock_list *entry;
-	int ret;
-
-	if (!__raw_spin_is_locked(&lockdep_lock))
-		return DEBUG_LOCKS_WARN_ON(1);
-
-	if (depth > max_recursion_depth)
-		max_recursion_depth = depth;
-	if (depth >= RECURSION_LIMIT)
-		return print_infinite_recursion_bug();
-
-	debug_atomic_inc(&nr_find_usage_backwards_checks);
-	if (source->usage_mask & (1 << find_usage_bit)) {
-		backwards_match = source;
-		return 2;
-	}
-
-	/*
-	 * Check this lock's dependency list:
-	 */
-	list_for_each_entry(entry, &source->locks_before, entry) {
-		debug_atomic_inc(&nr_find_usage_backwards_recursions);
-		ret = find_usage_backwards(entry->class, depth+1);
-		if (ret == 2 || ret == 0)
-			return ret;
-	}
-	return 1;
-}
-
-static int
-print_bad_irq_dependency(struct task_struct *curr,
-			 struct held_lock *prev,
-			 struct held_lock *next,
-			 enum lock_usage_bit bit1,
-			 enum lock_usage_bit bit2,
-			 const char *irqclass)
-{
-	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
-		return 0;
-
-	printk("\n======================================================\n");
-	printk(  "[ INFO: %s-safe -> %s-unsafe lock order detected ]\n",
-		irqclass, irqclass);
-	print_kernel_version();
-	printk(  "------------------------------------------------------\n");
-	printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] is trying to acquire:\n",
-		curr->comm, task_pid_nr(curr),
-		curr->hardirq_context, hardirq_count() >> HARDIRQ_SHIFT,
-		curr->softirq_context, softirq_count() >> SOFTIRQ_SHIFT,
-		curr->hardirqs_enabled,
-		curr->softirqs_enabled);
-	print_lock(next);
-
-	printk("\nand this task is already holding:\n");
-	print_lock(prev);
-	printk("which would create a new lock dependency:\n");
-	print_lock_name(prev->class);
-	printk(" ->");
-	print_lock_name(next->class);
-	printk("\n");
-
-	printk("\nbut this new dependency connects a %s-irq-safe lock:\n",
-		irqclass);
-	print_lock_name(backwards_match);
-	printk("\n... which became %s-irq-safe at:\n", irqclass);
-
-	print_stack_trace(backwards_match->usage_traces + bit1, 1);
-
-	printk("\nto a %s-irq-unsafe lock:\n", irqclass);
-	print_lock_name(forwards_match);
-	printk("\n... which became %s-irq-unsafe at:\n", irqclass);
-	printk("...");
-
-	print_stack_trace(forwards_match->usage_traces + bit2, 1);
-
-	printk("\nother info that might help us debug this:\n\n");
-	lockdep_print_held_locks(curr);
-
-	printk("\nthe %s-irq-safe lock's dependencies:\n", irqclass);
-	print_lock_dependencies(backwards_match, 0);
-
-	printk("\nthe %s-irq-unsafe lock's dependencies:\n", irqclass);
-	print_lock_dependencies(forwards_match, 0);
-
-	printk("\nstack backtrace:\n");
-	dump_stack();
-
-	return 0;
-}
-
-static int
-check_usage(struct task_struct *curr, struct held_lock *prev,
-	    struct held_lock *next, enum lock_usage_bit bit_backwards,
-	    enum lock_usage_bit bit_forwards, const char *irqclass)
-{
-	int ret;
-
-	find_usage_bit = bit_backwards;
-	/* fills in <backwards_match> */
-	ret = find_usage_backwards(prev->class, 0);
-	if (!ret || ret == 1)
-		return ret;
-
-	find_usage_bit = bit_forwards;
-	ret = find_usage_forwards(next->class, 0);
-	if (!ret || ret == 1)
-		return ret;
-	/* ret == 2 */
-	return print_bad_irq_dependency(curr, prev, next,
-			bit_backwards, bit_forwards, irqclass);
-}
-
-static int
-check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
-		struct held_lock *next)
-{
-	/*
-	 * Prove that the new dependency does not connect a hardirq-safe
-	 * lock with a hardirq-unsafe lock - to achieve this we search
-	 * the backwards-subgraph starting at <prev>, and the
-	 * forwards-subgraph starting at <next>:
-	 */
-	if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ,
-					LOCK_ENABLED_HARDIRQS, "hard"))
-		return 0;
-
-	/*
-	 * Prove that the new dependency does not connect a hardirq-safe-read
-	 * lock with a hardirq-unsafe lock - to achieve this we search
-	 * the backwards-subgraph starting at <prev>, and the
-	 * forwards-subgraph starting at <next>:
-	 */
-	if (!check_usage(curr, prev, next, LOCK_USED_IN_HARDIRQ_READ,
-					LOCK_ENABLED_HARDIRQS, "hard-read"))
-		return 0;
-
-	/*
-	 * Prove that the new dependency does not connect a softirq-safe
-	 * lock with a softirq-unsafe lock - to achieve this we search
-	 * the backwards-subgraph starting at <prev>, and the
-	 * forwards-subgraph starting at <next>:
-	 */
-	if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ,
-					LOCK_ENABLED_SOFTIRQS, "soft"))
-		return 0;
-	/*
-	 * Prove that the new dependency does not connect a softirq-safe-read
-	 * lock with a softirq-unsafe lock - to achieve this we search
-	 * the backwards-subgraph starting at <prev>, and the
-	 * forwards-subgraph starting at <next>:
-	 */
-	if (!check_usage(curr, prev, next, LOCK_USED_IN_SOFTIRQ_READ,
-					LOCK_ENABLED_SOFTIRQS, "soft"))
-		return 0;
-
-	return 1;
-}
-
-static void inc_chains(void)
-{
-	if (current->hardirq_context)
-		nr_hardirq_chains++;
-	else {
-		if (current->softirq_context)
-			nr_softirq_chains++;
-		else
-			nr_process_chains++;
-	}
-}
-
-#else
-
-static inline int
-check_prev_add_irq(struct task_struct *curr, struct held_lock *prev,
-		struct held_lock *next)
-{
-	return 1;
-}
-
-static inline void inc_chains(void)
-{
-	nr_process_chains++;
-}
-
-#endif
-
-static int
-print_deadlock_bug(struct task_struct *curr, struct held_lock *prev,
-		   struct held_lock *next)
-{
-	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
-		return 0;
-
-	printk("\n=============================================\n");
-	printk(  "[ INFO: possible recursive locking detected ]\n");
-	print_kernel_version();
-	printk(  "---------------------------------------------\n");
-	printk("%s/%d is trying to acquire lock:\n",
-		curr->comm, task_pid_nr(curr));
-	print_lock(next);
-	printk("\nbut task is already holding lock:\n");
-	print_lock(prev);
-
-	printk("\nother info that might help us debug this:\n");
-	lockdep_print_held_locks(curr);
-
-	printk("\nstack backtrace:\n");
-	dump_stack();
-
-	return 0;
-}
-
-/*
- * Check whether we are holding such a class already.
- *
- * (Note that this has to be done separately, because the graph cannot
- * detect such classes of deadlocks.)
- *
- * Returns: 0 on deadlock detected, 1 on OK, 2 on recursive read
- */
-static int
-check_deadlock(struct task_struct *curr, struct held_lock *next,
-	       struct lockdep_map *next_instance, int read)
-{
-	struct held_lock *prev;
-	int i;
-
-	for (i = 0; i < curr->lockdep_depth; i++) {
-		prev = curr->held_locks + i;
-		if (prev->class != next->class)
-			continue;
-		/*
-		 * Allow read-after-read recursion of the same
-		 * lock class (i.e. read_lock(lock)+read_lock(lock)):
-		 */
-		if ((read == 2) && prev->read)
-			return 2;
-		return print_deadlock_bug(curr, prev, next);
-	}
-	return 1;
-}
-
-/*
- * There was a chain-cache miss, and we are about to add a new dependency
- * to a previous lock. We recursively validate the following rules:
- *
- *  - would the adding of the <prev> -> <next> dependency create a
- *    circular dependency in the graph? [== circular deadlock]
- *
- *  - does the new prev->next dependency connect any hardirq-safe lock
- *    (in the full backwards-subgraph starting at <prev>) with any
- *    hardirq-unsafe lock (in the full forwards-subgraph starting at
- *    <next>)? [== illegal lock inversion with hardirq contexts]
- *
- *  - does the new prev->next dependency connect any softirq-safe lock
- *    (in the full backwards-subgraph starting at <prev>) with any
- *    softirq-unsafe lock (in the full forwards-subgraph starting at
- *    <next>)? [== illegal lock inversion with softirq contexts]
- *
- * any of these scenarios could lead to a deadlock.
- *
- * Then if all the validations pass, we add the forwards and backwards
- * dependency.
- */
-static int
-check_prev_add(struct task_struct *curr, struct held_lock *prev,
-	       struct held_lock *next, int distance)
-{
-	struct lock_list *entry;
-	int ret;
-
-	/*
-	 * Prove that the new <prev> -> <next> dependency would not
-	 * create a circular dependency in the graph. (We do this by
-	 * forward-recursing into the graph starting at <next>, and
-	 * checking whether we can reach <prev>.)
-	 *
-	 * We are using global variables to control the recursion, to
-	 * keep the stackframe size of the recursive functions low:
-	 */
-	check_source = next;
-	check_target = prev;
-	if (!(check_noncircular(next->class, 0)))
-		return print_circular_bug_tail();
-
-	if (!check_prev_add_irq(curr, prev, next))
-		return 0;
-
-	/*
-	 * For recursive read-locks we do all the dependency checks,
-	 * but we dont store read-triggered dependencies (only
-	 * write-triggered dependencies). This ensures that only the
-	 * write-side dependencies matter, and that if for example a
-	 * write-lock never takes any other locks, then the reads are
-	 * equivalent to a NOP.
-	 */
-	if (next->read == 2 || prev->read == 2)
-		return 1;
-	/*
-	 * Is the <prev> -> <next> dependency already present?
-	 *
-	 * (this may occur even though this is a new chain: consider
-	 *  e.g. the L1 -> L2 -> L3 -> L4 and the L5 -> L1 -> L2 -> L3
-	 *  chains - the second one will be new, but L1 already has
-	 *  L2 added to its dependency list, due to the first chain.)
-	 */
-	list_for_each_entry(entry, &prev->class->locks_after, entry) {
-		if (entry->class == next->class) {
-			if (distance == 1)
-				entry->distance = 1;
-			return 2;
-		}
-	}
-
-	/*
-	 * Ok, all validations passed, add the new lock
-	 * to the previous lock's dependency list:
-	 */
-	ret = add_lock_to_list(prev->class, next->class,
-			       &prev->class->locks_after, next->acquire_ip, distance);
-
-	if (!ret)
-		return 0;
-
-	ret = add_lock_to_list(next->class, prev->class,
-			       &next->class->locks_before, next->acquire_ip, distance);
-	if (!ret)
-		return 0;
-
-	/*
-	 * Debugging printouts:
-	 */
-	if (verbose(prev->class) || verbose(next->class)) {
-		graph_unlock();
-		printk("\n new dependency: ");
-		print_lock_name(prev->class);
-		printk(" => ");
-		print_lock_name(next->class);
-		printk("\n");
-		dump_stack();
-		return graph_lock();
-	}
-	return 1;
-}
-
-/*
- * Add the dependency to all directly-previous locks that are 'relevant'.
- * The ones that are relevant are (in increasing distance from curr):
- * all consecutive trylock entries and the final non-trylock entry - or
- * the end of this context's lock-chain - whichever comes first.
- */
-static int
-check_prevs_add(struct task_struct *curr, struct held_lock *next)
-{
-	int depth = curr->lockdep_depth;
-	struct held_lock *hlock;
-
-	/*
-	 * Debugging checks.
-	 *
-	 * Depth must not be zero for a non-head lock:
-	 */
-	if (!depth)
-		goto out_bug;
-	/*
-	 * At least two relevant locks must exist for this
-	 * to be a head:
-	 */
-	if (curr->held_locks[depth].irq_context !=
-			curr->held_locks[depth-1].irq_context)
-		goto out_bug;
-
-	for (;;) {
-		int distance = curr->lockdep_depth - depth + 1;
-		hlock = curr->held_locks + depth-1;
-		/*
-		 * Only non-recursive-read entries get new dependencies
-		 * added:
-		 */
-		if (hlock->read != 2) {
-			if (!check_prev_add(curr, hlock, next, distance))
-				return 0;
-			/*
-			 * Stop after the first non-trylock entry,
-			 * as non-trylock entries have added their
-			 * own direct dependencies already, so this
-			 * lock is connected to them indirectly:
-			 */
-			if (!hlock->trylock)
-				break;
-		}
-		depth--;
-		/*
-		 * End of lock-stack?
-		 */
-		if (!depth)
-			break;
-		/*
-		 * Stop the search if we cross into another context:
-		 */
-		if (curr->held_locks[depth].irq_context !=
-				curr->held_locks[depth-1].irq_context)
-			break;
-	}
-	return 1;
-out_bug:
-	if (!debug_locks_off_graph_unlock())
-		return 0;
-
-	WARN_ON(1);
-
-	return 0;
-}
-
-unsigned long nr_lock_chains;
-static struct lock_chain lock_chains[MAX_LOCKDEP_CHAINS];
-
-/*
- * Look up a dependency chain. If the key is not present yet then
- * add it and return 1 - in this case the new dependency chain is
- * validated. If the key is already hashed, return 0.
- * (On return with 1 graph_lock is held.)
- */
-static inline int lookup_chain_cache(u64 chain_key, struct lock_class *class)
-{
-	struct list_head *hash_head = chainhashentry(chain_key);
-	struct lock_chain *chain;
-
-	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
-		return 0;
-	/*
-	 * We can walk it lock-free, because entries only get added
-	 * to the hash:
-	 */
-	list_for_each_entry(chain, hash_head, entry) {
-		if (chain->chain_key == chain_key) {
-cache_hit:
-			debug_atomic_inc(&chain_lookup_hits);
-			if (very_verbose(class))
-				printk("\nhash chain already cached, key: "
-					"%016Lx tail class: [%p] %s\n",
-					(unsigned long long)chain_key,
-					class->key, class->name);
-			return 0;
-		}
-	}
-	if (very_verbose(class))
-		printk("\nnew hash chain, key: %016Lx tail class: [%p] %s\n",
-			(unsigned long long)chain_key, class->key, class->name);
-	/*
-	 * Allocate a new chain entry from the static array, and add
-	 * it to the hash:
-	 */
-	if (!graph_lock())
-		return 0;
-	/*
-	 * We have to walk the chain again locked - to avoid duplicates:
-	 */
-	list_for_each_entry(chain, hash_head, entry) {
-		if (chain->chain_key == chain_key) {
-			graph_unlock();
-			goto cache_hit;
-		}
-	}
-	if (unlikely(nr_lock_chains >= MAX_LOCKDEP_CHAINS)) {
-		if (!debug_locks_off_graph_unlock())
-			return 0;
-
-		printk("BUG: MAX_LOCKDEP_CHAINS too low!\n");
-		printk("turning off the locking correctness validator.\n");
-		return 0;
-	}
-	chain = lock_chains + nr_lock_chains++;
-	chain->chain_key = chain_key;
-	list_add_tail_rcu(&chain->entry, hash_head);
-	debug_atomic_inc(&chain_lookup_misses);
-	inc_chains();
-
-	return 1;
-}
-
-static int validate_chain(struct task_struct *curr, struct lockdep_map *lock,
-		struct held_lock *hlock, int chain_head, u64 chain_key)
-{
-	/*
-	 * Trylock needs to maintain the stack of held locks, but it
-	 * does not add new dependencies, because trylock can be done
-	 * in any order.
-	 *
-	 * We look up the chain_key and do the O(N^2) check and update of
-	 * the dependencies only if this is a new dependency chain.
-	 * (If lookup_chain_cache() returns with 1 it acquires
-	 * graph_lock for us)
-	 */
-	if (!hlock->trylock && (hlock->check == 2) &&
-			lookup_chain_cache(chain_key, hlock->class)) {
-		/*
-		 * Check whether last held lock:
-		 *
-		 * - is irq-safe, if this lock is irq-unsafe
-		 * - is softirq-safe, if this lock is hardirq-unsafe
-		 *
-		 * And check whether the new lock's dependency graph
-		 * could lead back to the previous lock.
-		 *
-		 * any of these scenarios could lead to a deadlock. If
-		 * All validations
-		 */
-		int ret = check_deadlock(curr, hlock, lock, hlock->read);
-
-		if (!ret)
-			return 0;
-		/*
-		 * Mark recursive read, as we jump over it when
-		 * building dependencies (just like we jump over
-		 * trylock entries):
-		 */
-		if (ret == 2)
-			hlock->read = 2;
-		/*
-		 * Add dependency only if this lock is not the head
-		 * of the chain, and if it's not a secondary read-lock:
-		 */
-		if (!chain_head && ret != 2)
-			if (!check_prevs_add(curr, hlock))
-				return 0;
-		graph_unlock();
-	} else
-		/* after lookup_chain_cache(): */
-		if (unlikely(!debug_locks))
-			return 0;
-
-	return 1;
-}
-#else
-static inline int validate_chain(struct task_struct *curr,
-	       	struct lockdep_map *lock, struct held_lock *hlock,
-		int chain_head, u64 chain_key)
-{
-	return 1;
-}
-#endif
-
-/*
- * We are building curr_chain_key incrementally, so double-check
- * it from scratch, to make sure that it's done correctly:
- */
-static void check_chain_key(struct task_struct *curr)
-{
-#ifdef CONFIG_DEBUG_LOCKDEP
-	struct held_lock *hlock, *prev_hlock = NULL;
-	unsigned int i, id;
-	u64 chain_key = 0;
-
-	for (i = 0; i < curr->lockdep_depth; i++) {
-		hlock = curr->held_locks + i;
-		if (chain_key != hlock->prev_chain_key) {
-			debug_locks_off();
-			printk("hm#1, depth: %u [%u], %016Lx != %016Lx\n",
-				curr->lockdep_depth, i,
-				(unsigned long long)chain_key,
-				(unsigned long long)hlock->prev_chain_key);
-			WARN_ON(1);
-			return;
-		}
-		id = hlock->class - lock_classes;
-		if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
-			return;
-
-		if (prev_hlock && (prev_hlock->irq_context !=
-							hlock->irq_context))
-			chain_key = 0;
-		chain_key = iterate_chain_key(chain_key, id);
-		prev_hlock = hlock;
-	}
-	if (chain_key != curr->curr_chain_key) {
-		debug_locks_off();
-		printk("hm#2, depth: %u [%u], %016Lx != %016Lx\n",
-			curr->lockdep_depth, i,
-			(unsigned long long)chain_key,
-			(unsigned long long)curr->curr_chain_key);
-		WARN_ON(1);
-	}
-#endif
-}
-
-static int
-print_usage_bug(struct task_struct *curr, struct held_lock *this,
-		enum lock_usage_bit prev_bit, enum lock_usage_bit new_bit)
-{
-	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
-		return 0;
-
-	printk("\n=================================\n");
-	printk(  "[ INFO: inconsistent lock state ]\n");
-	print_kernel_version();
-	printk(  "---------------------------------\n");
-
-	printk("inconsistent {%s} -> {%s} usage.\n",
-		usage_str[prev_bit], usage_str[new_bit]);
-
-	printk("%s/%d [HC%u[%lu]:SC%u[%lu]:HE%u:SE%u] takes:\n",
-		curr->comm, task_pid_nr(curr),
-		trace_hardirq_context(curr), hardirq_count() >> HARDIRQ_SHIFT,
-		trace_softirq_context(curr), softirq_count() >> SOFTIRQ_SHIFT,
-		trace_hardirqs_enabled(curr),
-		trace_softirqs_enabled(curr));
-	print_lock(this);
-
-	printk("{%s} state was registered at:\n", usage_str[prev_bit]);
-	print_stack_trace(this->class->usage_traces + prev_bit, 1);
-
-	print_irqtrace_events(curr);
-	printk("\nother info that might help us debug this:\n");
-	lockdep_print_held_locks(curr);
-
-	printk("\nstack backtrace:\n");
-	dump_stack();
-
-	return 0;
-}
-
-/*
- * Print out an error if an invalid bit is set:
- */
-static inline int
-valid_state(struct task_struct *curr, struct held_lock *this,
-	    enum lock_usage_bit new_bit, enum lock_usage_bit bad_bit)
-{
-	if (unlikely(this->class->usage_mask & (1 << bad_bit)))
-		return print_usage_bug(curr, this, bad_bit, new_bit);
-	return 1;
-}
-
-static int mark_lock(struct task_struct *curr, struct held_lock *this,
-		     enum lock_usage_bit new_bit);
-
-#ifdef CONFIG_TRACE_IRQFLAGS
-
-/*
- * print irq inversion bug:
- */
-static int
-print_irq_inversion_bug(struct task_struct *curr, struct lock_class *other,
-			struct held_lock *this, int forwards,
-			const char *irqclass)
-{
-	if (!debug_locks_off_graph_unlock() || debug_locks_silent)
-		return 0;
-
-	printk("\n=========================================================\n");
-	printk(  "[ INFO: possible irq lock inversion dependency detected ]\n");
-	print_kernel_version();
-	printk(  "---------------------------------------------------------\n");
-	printk("%s/%d just changed the state of lock:\n",
-		curr->comm, task_pid_nr(curr));
-	print_lock(this);
-	if (forwards)
-		printk("but this lock took another, %s-irq-unsafe lock in the past:\n", irqclass);
-	else
-		printk("but this lock was taken by another, %s-irq-safe lock in the past:\n", irqclass);
-	print_lock_name(other);
-	printk("\n\nand interrupts could create inverse lock ordering between them.\n\n");
-
-	printk("\nother info that might help us debug this:\n");
-	lockdep_print_held_locks(curr);
-
-	printk("\nthe first lock's dependencies:\n");
-	print_lock_dependencies(this->class, 0);
-
-	printk("\nthe second lock's dependencies:\n");
-	print_lock_dependencies(other, 0);
-
-	printk("\nstack backtrace:\n");
-	dump_stack();
-
-	return 0;
-}
-
-/*
- * Prove that in the forwards-direction subgraph starting at <this>
- * there is no lock matching <mask>:
- */
-static int
-check_usage_forwards(struct task_struct *curr, struct held_lock *this,
-		     enum lock_usage_bit bit, const char *irqclass)
-{
-	int ret;
-
-	find_usage_bit = bit;
-	/* fills in <forwards_match> */
-	ret = find_usage_forwards(this->class, 0);
-	if (!ret || ret == 1)
-		return ret;
-
-	return print_irq_inversion_bug(curr, forwards_match, this, 1, irqclass);
-}
-
-/*
- * Prove that in the backwards-direction subgraph starting at <this>
- * there is no lock matching <mask>:
- */
-static int
-check_usage_backwards(struct task_struct *curr, struct held_lock *this,
-		      enum lock_usage_bit bit, const char *irqclass)
-{
-	int ret;
-
-	find_usage_bit = bit;
-	/* fills in <backwards_match> */
-	ret = find_usage_backwards(this->class, 0);
-	if (!ret || ret == 1)
-		return ret;
-
-	return print_irq_inversion_bug(curr, backwards_match, this, 0, irqclass);
-}
-
-void print_irqtrace_events(struct task_struct *curr)
-{
-	printk("irq event stamp: %u\n", curr->irq_events);
-	printk("hardirqs last  enabled at (%u): ", curr->hardirq_enable_event);
-	print_ip_sym(curr->hardirq_enable_ip);
-	printk("hardirqs last disabled at (%u): ", curr->hardirq_disable_event);
-	print_ip_sym(curr->hardirq_disable_ip);
-	printk("softirqs last  enabled at (%u): ", curr->softirq_enable_event);
-	print_ip_sym(curr->softirq_enable_ip);
-	printk("softirqs last disabled at (%u): ", curr->softirq_disable_event);
-	print_ip_sym(curr->softirq_disable_ip);
-}
-
-static int hardirq_verbose(struct lock_class *class)
-{
-#if HARDIRQ_VERBOSE
-	return class_filter(class);
-#endif
-	return 0;
-}
-
-static int softirq_verbose(struct lock_class *class)
-{
-#if SOFTIRQ_VERBOSE
-	return class_filter(class);
-#endif
-	return 0;
-}
-
-#define STRICT_READ_CHECKS	1
-
-static int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
-		enum lock_usage_bit new_bit)
-{
-	int ret = 1;
-
-	switch(new_bit) {
-	case LOCK_USED_IN_HARDIRQ:
-		if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS))
-			return 0;
-		if (!valid_state(curr, this, new_bit,
-				 LOCK_ENABLED_HARDIRQS_READ))
-			return 0;
-		/*
-		 * just marked it hardirq-safe, check that this lock
-		 * took no hardirq-unsafe lock in the past:
-		 */
-		if (!check_usage_forwards(curr, this,
-					  LOCK_ENABLED_HARDIRQS, "hard"))
-			return 0;
-#if STRICT_READ_CHECKS
-		/*
-		 * just marked it hardirq-safe, check that this lock
-		 * took no hardirq-unsafe-read lock in the past:
-		 */
-		if (!check_usage_forwards(curr, this,
-				LOCK_ENABLED_HARDIRQS_READ, "hard-read"))
-			return 0;
-#endif
-		if (hardirq_verbose(this->class))
-			ret = 2;
-		break;
-	case LOCK_USED_IN_SOFTIRQ:
-		if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS))
-			return 0;
-		if (!valid_state(curr, this, new_bit,
-				 LOCK_ENABLED_SOFTIRQS_READ))
-			return 0;
-		/*
-		 * just marked it softirq-safe, check that this lock
-		 * took no softirq-unsafe lock in the past:
-		 */
-		if (!check_usage_forwards(curr, this,
-					  LOCK_ENABLED_SOFTIRQS, "soft"))
-			return 0;
-#if STRICT_READ_CHECKS
-		/*
-		 * just marked it softirq-safe, check that this lock
-		 * took no softirq-unsafe-read lock in the past:
-		 */
-		if (!check_usage_forwards(curr, this,
-				LOCK_ENABLED_SOFTIRQS_READ, "soft-read"))
-			return 0;
-#endif
-		if (softirq_verbose(this->class))
-			ret = 2;
-		break;
-	case LOCK_USED_IN_HARDIRQ_READ:
-		if (!valid_state(curr, this, new_bit, LOCK_ENABLED_HARDIRQS))
-			return 0;
-		/*
-		 * just marked it hardirq-read-safe, check that this lock
-		 * took no hardirq-unsafe lock in the past:
-		 */
-		if (!check_usage_forwards(curr, this,
-					  LOCK_ENABLED_HARDIRQS, "hard"))
-			return 0;
-		if (hardirq_verbose(this->class))
-			ret = 2;
-		break;
-	case LOCK_USED_IN_SOFTIRQ_READ:
-		if (!valid_state(curr, this, new_bit, LOCK_ENABLED_SOFTIRQS))
-			return 0;
-		/*
-		 * just marked it softirq-read-safe, check that this lock
-		 * took no softirq-unsafe lock in the past:
-		 */
-		if (!check_usage_forwards(curr, this,
-					  LOCK_ENABLED_SOFTIRQS, "soft"))
-			return 0;
-		if (softirq_verbose(this->class))
-			ret = 2;
-		break;
-	case LOCK_ENABLED_HARDIRQS:
-		if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ))
-			return 0;
-		if (!valid_state(curr, this, new_bit,
-				 LOCK_USED_IN_HARDIRQ_READ))
-			return 0;
-		/*
-		 * just marked it hardirq-unsafe, check that no hardirq-safe
-		 * lock in the system ever took it in the past:
-		 */
-		if (!check_usage_backwards(curr, this,
-					   LOCK_USED_IN_HARDIRQ, "hard"))
-			return 0;
-#if STRICT_READ_CHECKS
-		/*
-		 * just marked it hardirq-unsafe, check that no
-		 * hardirq-safe-read lock in the system ever took
-		 * it in the past:
-		 */
-		if (!check_usage_backwards(curr, this,
-				   LOCK_USED_IN_HARDIRQ_READ, "hard-read"))
-			return 0;
-#endif
-		if (hardirq_verbose(this->class))
-			ret = 2;
-		break;
-	case LOCK_ENABLED_SOFTIRQS:
-		if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ))
-			return 0;
-		if (!valid_state(curr, this, new_bit,
-				 LOCK_USED_IN_SOFTIRQ_READ))
-			return 0;
-		/*
-		 * just marked it softirq-unsafe, check that no softirq-safe
-		 * lock in the system ever took it in the past:
-		 */
-		if (!check_usage_backwards(curr, this,
-					   LOCK_USED_IN_SOFTIRQ, "soft"))
-			return 0;
-#if STRICT_READ_CHECKS
-		/*
-		 * just marked it softirq-unsafe, check that no
-		 * softirq-safe-read lock in the system ever took
-		 * it in the past:
-		 */
-		if (!check_usage_backwards(curr, this,
-				   LOCK_USED_IN_SOFTIRQ_READ, "soft-read"))
-			return 0;
-#endif
-		if (softirq_verbose(this->class))
-			ret = 2;
-		break;
-	case LOCK_ENABLED_HARDIRQS_READ:
-		if (!valid_state(curr, this, new_bit, LOCK_USED_IN_HARDIRQ))
-			return 0;
-#if STRICT_READ_CHECKS
-		/*
-		 * just marked it hardirq-read-unsafe, check that no
-		 * hardirq-safe lock in the system ever took it in the past:
-		 */
-		if (!check_usage_backwards(curr, this,
-					   LOCK_USED_IN_HARDIRQ, "hard"))
-			return 0;
-#endif
-		if (hardirq_verbose(this->class))
-			ret = 2;
-		break;
-	case LOCK_ENABLED_SOFTIRQS_READ:
-		if (!valid_state(curr, this, new_bit, LOCK_USED_IN_SOFTIRQ))
-			return 0;
-#if STRICT_READ_CHECKS
-		/*
-		 * just marked it softirq-read-unsafe, check that no
-		 * softirq-safe lock in the system ever took it in the past:
-		 */
-		if (!check_usage_backwards(curr, this,
-					   LOCK_USED_IN_SOFTIRQ, "soft"))
-			return 0;
-#endif
-		if (softirq_verbose(this->class))
-			ret = 2;
-		break;
-	default:
-		WARN_ON(1);
-		break;
-	}
-
-	return ret;
-}
-
-/*
- * Mark all held locks with a usage bit:
- */
-static int
-mark_held_locks(struct task_struct *curr, int hardirq)
-{
-	enum lock_usage_bit usage_bit;
-	struct held_lock *hlock;
-	int i;
-
-	for (i = 0; i < curr->lockdep_depth; i++) {
-		hlock = curr->held_locks + i;
-
-		if (hardirq) {
-			if (hlock->read)
-				usage_bit = LOCK_ENABLED_HARDIRQS_READ;
-			else
-				usage_bit = LOCK_ENABLED_HARDIRQS;
-		} else {
-			if (hlock->read)
-				usage_bit = LOCK_ENABLED_SOFTIRQS_READ;
-			else
-				usage_bit = LOCK_ENABLED_SOFTIRQS;
-		}
-		if (!mark_lock(curr, hlock, usage_bit))
-			return 0;
-	}
-
-	return 1;
-}
-
-/*
- * Debugging helper: via this flag we know that we are in
- * 'early bootup code', and will warn about any invalid irqs-on event:
- */
-static int early_boot_irqs_enabled;
-
-void early_boot_irqs_off(void)
-{
-	early_boot_irqs_enabled = 0;
-}
-
-void early_boot_irqs_on(void)
-{
-	early_boot_irqs_enabled = 1;
-}
-
-/*
- * Hardirqs will be enabled:
- */
-void trace_hardirqs_on(void)
-{
-	struct task_struct *curr = current;
-	unsigned long ip;
-
-	if (unlikely(!debug_locks || current->lockdep_recursion))
-		return;
-
-	if (DEBUG_LOCKS_WARN_ON(unlikely(!early_boot_irqs_enabled)))
-		return;
-
-	if (unlikely(curr->hardirqs_enabled)) {
-		debug_atomic_inc(&redundant_hardirqs_on);
-		return;
-	}
-	/* we'll do an OFF -> ON transition: */
-	curr->hardirqs_enabled = 1;
-	ip = (unsigned long) __builtin_return_address(0);
-
-	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
-		return;
-	if (DEBUG_LOCKS_WARN_ON(current->hardirq_context))
-		return;
-	/*
-	 * We are going to turn hardirqs on, so set the
-	 * usage bit for all held locks:
-	 */
-	if (!mark_held_locks(curr, 1))
-		return;
-	/*
-	 * If we have softirqs enabled, then set the usage
-	 * bit for all held locks. (disabled hardirqs prevented
-	 * this bit from being set before)
-	 */
-	if (curr->softirqs_enabled)
-		if (!mark_held_locks(curr, 0))
-			return;
-
-	curr->hardirq_enable_ip = ip;
-	curr->hardirq_enable_event = ++curr->irq_events;
-	debug_atomic_inc(&hardirqs_on_events);
-}
-
-EXPORT_SYMBOL(trace_hardirqs_on);
-
-/*
- * Hardirqs were disabled:
- */
-void trace_hardirqs_off(void)
-{
-	struct task_struct *curr = current;
-
-	if (unlikely(!debug_locks || current->lockdep_recursion))
-		return;
-
-	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
-		return;
-
-	if (curr->hardirqs_enabled) {
-		/*
-		 * We have done an ON -> OFF transition:
-		 */
-		curr->hardirqs_enabled = 0;
-		curr->hardirq_disable_ip = _RET_IP_;
-		curr->hardirq_disable_event = ++curr->irq_events;
-		debug_atomic_inc(&hardirqs_off_events);
-	} else
-		debug_atomic_inc(&redundant_hardirqs_off);
-}
-
-EXPORT_SYMBOL(trace_hardirqs_off);
-
-/*
- * Softirqs will be enabled:
- */
-void trace_softirqs_on(unsigned long ip)
-{
-	struct task_struct *curr = current;
-
-	if (unlikely(!debug_locks))
-		return;
-
-	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
-		return;
-
-	if (curr->softirqs_enabled) {
-		debug_atomic_inc(&redundant_softirqs_on);
-		return;
-	}
-
-	/*
-	 * We'll do an OFF -> ON transition:
-	 */
-	curr->softirqs_enabled = 1;
-	curr->softirq_enable_ip = ip;
-	curr->softirq_enable_event = ++curr->irq_events;
-	debug_atomic_inc(&softirqs_on_events);
-	/*
-	 * We are going to turn softirqs on, so set the
-	 * usage bit for all held locks, if hardirqs are
-	 * enabled too:
-	 */
-	if (curr->hardirqs_enabled)
-		mark_held_locks(curr, 0);
-}
-
-/*
- * Softirqs were disabled:
- */
-void trace_softirqs_off(unsigned long ip)
-{
-	struct task_struct *curr = current;
-
-	if (unlikely(!debug_locks))
-		return;
-
-	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
-		return;
-
-	if (curr->softirqs_enabled) {
-		/*
-		 * We have done an ON -> OFF transition:
-		 */
-		curr->softirqs_enabled = 0;
-		curr->softirq_disable_ip = ip;
-		curr->softirq_disable_event = ++curr->irq_events;
-		debug_atomic_inc(&softirqs_off_events);
-		DEBUG_LOCKS_WARN_ON(!softirq_count());
-	} else
-		debug_atomic_inc(&redundant_softirqs_off);
-}
-
-static int mark_irqflags(struct task_struct *curr, struct held_lock *hlock)
-{
-	/*
-	 * If non-trylock use in a hardirq or softirq context, then
-	 * mark the lock as used in these contexts:
-	 */
-	if (!hlock->trylock) {
-		if (hlock->read) {
-			if (curr->hardirq_context)
-				if (!mark_lock(curr, hlock,
-						LOCK_USED_IN_HARDIRQ_READ))
-					return 0;
-			if (curr->softirq_context)
-				if (!mark_lock(curr, hlock,
-						LOCK_USED_IN_SOFTIRQ_READ))
-					return 0;
-		} else {
-			if (curr->hardirq_context)
-				if (!mark_lock(curr, hlock, LOCK_USED_IN_HARDIRQ))
-					return 0;
-			if (curr->softirq_context)
-				if (!mark_lock(curr, hlock, LOCK_USED_IN_SOFTIRQ))
-					return 0;
-		}
-	}
-	if (!hlock->hardirqs_off) {
-		if (hlock->read) {
-			if (!mark_lock(curr, hlock,
-					LOCK_ENABLED_HARDIRQS_READ))
-				return 0;
-			if (curr->softirqs_enabled)
-				if (!mark_lock(curr, hlock,
-						LOCK_ENABLED_SOFTIRQS_READ))
-					return 0;
-		} else {
-			if (!mark_lock(curr, hlock,
-					LOCK_ENABLED_HARDIRQS))
-				return 0;
-			if (curr->softirqs_enabled)
-				if (!mark_lock(curr, hlock,
-						LOCK_ENABLED_SOFTIRQS))
-					return 0;
-		}
-	}
-
-	return 1;
-}
-
-static int separate_irq_context(struct task_struct *curr,
-		struct held_lock *hlock)
-{
-	unsigned int depth = curr->lockdep_depth;
-
-	/*
-	 * Keep track of points where we cross into an interrupt context:
-	 */
-	hlock->irq_context = 2*(curr->hardirq_context ? 1 : 0) +
-				curr->softirq_context;
-	if (depth) {
-		struct held_lock *prev_hlock;
-
-		prev_hlock = curr->held_locks + depth-1;
-		/*
-		 * If we cross into another context, reset the
-		 * hash key (this also prevents the checking and the
-		 * adding of the dependency to 'prev'):
-		 */
-		if (prev_hlock->irq_context != hlock->irq_context)
-			return 1;
-	}
-	return 0;
-}
-
-#else
-
-static inline
-int mark_lock_irq(struct task_struct *curr, struct held_lock *this,
-		enum lock_usage_bit new_bit)
-{
-	WARN_ON(1);
-	return 1;
-}
-
-static inline int mark_irqflags(struct task_struct *curr,
-		struct held_lock *hlock)
-{
-	return 1;
-}
-
-static inline int separate_irq_context(struct task_struct *curr,
-		struct held_lock *hlock)
-{
-	return 0;
-}
-
-#endif
-
-/*
- * Mark a lock with a usage bit, and validate the state transition:
- */
-static int mark_lock(struct task_struct *curr, struct held_lock *this,
-		     enum lock_usage_bit new_bit)
-{
-	unsigned int new_mask = 1 << new_bit, ret = 1;
-
-	/*
-	 * If already set then do not dirty the cacheline,
-	 * nor do any checks:
-	 */
-	if (likely(this->class->usage_mask & new_mask))
-		return 1;
-
-	if (!graph_lock())
-		return 0;
-	/*
-	 * Make sure we didnt race:
-	 */
-	if (unlikely(this->class->usage_mask & new_mask)) {
-		graph_unlock();
-		return 1;
-	}
-
-	this->class->usage_mask |= new_mask;
-
-	if (!save_trace(this->class->usage_traces + new_bit))
-		return 0;
-
-	switch (new_bit) {
-	case LOCK_USED_IN_HARDIRQ:
-	case LOCK_USED_IN_SOFTIRQ:
-	case LOCK_USED_IN_HARDIRQ_READ:
-	case LOCK_USED_IN_SOFTIRQ_READ:
-	case LOCK_ENABLED_HARDIRQS:
-	case LOCK_ENABLED_SOFTIRQS:
-	case LOCK_ENABLED_HARDIRQS_READ:
-	case LOCK_ENABLED_SOFTIRQS_READ:
-		ret = mark_lock_irq(curr, this, new_bit);
-		if (!ret)
-			return 0;
-		break;
-	case LOCK_USED:
-		/*
-		 * Add it to the global list of classes:
-		 */
-		list_add_tail_rcu(&this->class->lock_entry, &all_lock_classes);
-		debug_atomic_dec(&nr_unused_locks);
-		break;
-	default:
-		if (!debug_locks_off_graph_unlock())
-			return 0;
-		WARN_ON(1);
-		return 0;
-	}
-
-	graph_unlock();
-
-	/*
-	 * We must printk outside of the graph_lock:
-	 */
-	if (ret == 2) {
-		printk("\nmarked lock as {%s}:\n", usage_str[new_bit]);
-		print_lock(this);
-		print_irqtrace_events(curr);
-		dump_stack();
-	}
-
-	return ret;
-}
-
-/*
- * Initialize a lock instance's lock-class mapping info:
- */
-void lockdep_init_map(struct lockdep_map *lock, const char *name,
-		      struct lock_class_key *key, int subclass)
-{
-	if (unlikely(!debug_locks))
-		return;
-
-	if (DEBUG_LOCKS_WARN_ON(!key))
-		return;
-	if (DEBUG_LOCKS_WARN_ON(!name))
-		return;
-	/*
-	 * Sanity check, the lock-class key must be persistent:
-	 */
-	if (!static_obj(key)) {
-		printk("BUG: key %p not in .data!\n", key);
-		DEBUG_LOCKS_WARN_ON(1);
-		return;
-	}
-	lock->name = name;
-	lock->key = key;
-	lock->class_cache = NULL;
-#ifdef CONFIG_LOCK_STAT
-	lock->cpu = raw_smp_processor_id();
-#endif
-	if (subclass)
-		register_lock_class(lock, subclass, 1);
-}
-
-EXPORT_SYMBOL_GPL(lockdep_init_map);
-
-/*
- * This gets called for every mutex_lock*()/spin_lock*() operation.
- * We maintain the dependency maps and validate the locking attempt:
- */
-static int __lock_acquire(struct lockdep_map *lock, unsigned int subclass,
-			  int trylock, int read, int check, int hardirqs_off,
-			  unsigned long ip)
-{
-	struct task_struct *curr = current;
-	struct lock_class *class = NULL;
-	struct held_lock *hlock;
-	unsigned int depth, id;
-	int chain_head = 0;
-	u64 chain_key;
-
-	if (!prove_locking)
-		check = 1;
-
-	if (unlikely(!debug_locks))
-		return 0;
-
-	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
-		return 0;
-
-	if (unlikely(subclass >= MAX_LOCKDEP_SUBCLASSES)) {
-		debug_locks_off();
-		printk("BUG: MAX_LOCKDEP_SUBCLASSES too low!\n");
-		printk("turning off the locking correctness validator.\n");
-		return 0;
-	}
-
-	if (!subclass)
-		class = lock->class_cache;
-	/*
-	 * Not cached yet or subclass?
-	 */
-	if (unlikely(!class)) {
-		class = register_lock_class(lock, subclass, 0);
-		if (!class)
-			return 0;
-	}
-	debug_atomic_inc((atomic_t *)&class->ops);
-	if (very_verbose(class)) {
-		printk("\nacquire class [%p] %s", class->key, class->name);
-		if (class->name_version > 1)
-			printk("#%d", class->name_version);
-		printk("\n");
-		dump_stack();
-	}
-
-	/*
-	 * Add the lock to the list of currently held locks.
-	 * (we dont increase the depth just yet, up until the
-	 * dependency checks are done)
-	 */
-	depth = curr->lockdep_depth;
-	if (DEBUG_LOCKS_WARN_ON(depth >= MAX_LOCK_DEPTH))
-		return 0;
-
-	hlock = curr->held_locks + depth;
-
-	hlock->class = class;
-	hlock->acquire_ip = ip;
-	hlock->instance = lock;
-	hlock->trylock = trylock;
-	hlock->read = read;
-	hlock->check = check;
-	hlock->hardirqs_off = hardirqs_off;
-#ifdef CONFIG_LOCK_STAT
-	hlock->waittime_stamp = 0;
-	hlock->holdtime_stamp = sched_clock();
-#endif
-
-	if (check == 2 && !mark_irqflags(curr, hlock))
-		return 0;
-
-	/* mark it as used: */
-	if (!mark_lock(curr, hlock, LOCK_USED))
-		return 0;
-
-	/*
-	 * Calculate the chain hash: it's the combined has of all the
-	 * lock keys along the dependency chain. We save the hash value
-	 * at every step so that we can get the current hash easily
-	 * after unlock. The chain hash is then used to cache dependency
-	 * results.
-	 *
-	 * The 'key ID' is what is the most compact key value to drive
-	 * the hash, not class->key.
-	 */
-	id = class - lock_classes;
-	if (DEBUG_LOCKS_WARN_ON(id >= MAX_LOCKDEP_KEYS))
-		return 0;
-
-	chain_key = curr->curr_chain_key;
-	if (!depth) {
-		if (DEBUG_LOCKS_WARN_ON(chain_key != 0))
-			return 0;
-		chain_head = 1;
-	}
-
-	hlock->prev_chain_key = chain_key;
-	if (separate_irq_context(curr, hlock)) {
-		chain_key = 0;
-		chain_head = 1;
-	}
-	chain_key = iterate_chain_key(chain_key, id);
-
-	if (!validate_chain(curr, lock, hlock, chain_head, chain_key))
-		return 0;
-
-	curr->curr_chain_key = chain_key;
-	curr->lockdep_depth++;
-	check_chain_key(curr);
-#ifdef CONFIG_DEBUG_LOCKDEP
-	if (unlikely(!debug_locks))
-		return 0;
-#endif
-	if (unlikely(curr->lockdep_depth >= MAX_LOCK_DEPTH)) {
-		debug_locks_off();
-		printk("BUG: MAX_LOCK_DEPTH too low!\n");
-		printk("turning off the locking correctness validator.\n");
-		return 0;
-	}
-
-	if (unlikely(curr->lockdep_depth > max_lockdep_depth))
-		max_lockdep_depth = curr->lockdep_depth;
-
-	return 1;
-}
-
-static int
-print_unlock_inbalance_bug(struct task_struct *curr, struct lockdep_map *lock,
-			   unsigned long ip)
-{
-	if (!debug_locks_off())
-		return 0;
-	if (debug_locks_silent)
-		return 0;
-
-	printk("\n=====================================\n");
-	printk(  "[ BUG: bad unlock balance detected! ]\n");
-	printk(  "-------------------------------------\n");
-	printk("%s/%d is trying to release lock (",
-		curr->comm, task_pid_nr(curr));
-	print_lockdep_cache(lock);
-	printk(") at:\n");
-	print_ip_sym(ip);
-	printk("but there are no more locks to release!\n");
-	printk("\nother info that might help us debug this:\n");
-	lockdep_print_held_locks(curr);
-
-	printk("\nstack backtrace:\n");
-	dump_stack();
-
-	return 0;
-}
-
-/*
- * Common debugging checks for both nested and non-nested unlock:
- */
-static int check_unlock(struct task_struct *curr, struct lockdep_map *lock,
-			unsigned long ip)
-{
-	if (unlikely(!debug_locks))
-		return 0;
-	if (DEBUG_LOCKS_WARN_ON(!irqs_disabled()))
-		return 0;
-
-	if (curr->lockdep_depth <= 0)
-		return print_unlock_inbalance_bug(curr, lock, ip);
-
-	return 1;
-}
-
-/*
- * Remove the lock to the list of currently held locks in a
- * potentially non-nested (out of order) manner. This is a
- * relatively rare operation, as all the unlock APIs default
- * to nested mode (which uses lock_release()):
- */
-static int
-lock_release_non_nested(struct task_struct *curr,
-			struct lockdep_map *lock, unsigned long ip)
-{
-	struct held_lock *hlock, *prev_hlock;
-	unsigned int depth;
-	int i;
-
-	/*
-	 * Check whether the lock exists in the current stack
-	 * of held locks:
-	 */
-	depth = curr->lockdep_depth;
-	if (DEBUG_LOCKS_WARN_ON(!depth))
-		return 0;
-
-	prev_hlock = NULL;
-	for (i = depth-1; i >= 0; i--) {
-		hlock = curr->held_locks + i;
-		/*
-		 * We must not cross into another context:
-		 */
-		if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
-			break;
-		if (hlock->instance == lock)
-			goto found_it;
-		prev_hlock = hlock;
-	}
-	return print_unlock_inbalance_bug(curr, lock, ip);
-
-found_it:
-	lock_release_holdtime(hlock);
-
-	/*
-	 * We have the right lock to unlock, 'hlock' points to it.
-	 * Now we remove it from the stack, and add back the other
-	 * entries (if any), recalculating the hash along the way:
-	 */
-	curr->lockdep_depth = i;
-	curr->curr_chain_key = hlock->prev_chain_key;
-
-	for (i++; i < depth; i++) {
-		hlock = curr->held_locks + i;
-		if (!__lock_acquire(hlock->instance,
-			hlock->class->subclass, hlock->trylock,
-				hlock->read, hlock->check, hlock->hardirqs_off,
-				hlock->acquire_ip))
-			return 0;
-	}
-
-	if (DEBUG_LOCKS_WARN_ON(curr->lockdep_depth != depth - 1))
-		return 0;
-	return 1;
-}
-
-/*
- * Remove the lock to the list of currently held locks - this gets
- * called on mutex_unlock()/spin_unlock*() (or on a failed
- * mutex_lock_interruptible()). This is done for unlocks that nest
- * perfectly. (i.e. the current top of the lock-stack is unlocked)
- */
-static int lock_release_nested(struct task_struct *curr,
-			       struct lockdep_map *lock, unsigned long ip)
-{
-	struct held_lock *hlock;
-	unsigned int depth;
-
-	/*
-	 * Pop off the top of the lock stack:
-	 */
-	depth = curr->lockdep_depth - 1;
-	hlock = curr->held_locks + depth;
-
-	/*
-	 * Is the unlock non-nested:
-	 */
-	if (hlock->instance != lock)
-		return lock_release_non_nested(curr, lock, ip);
-	curr->lockdep_depth--;
-
-	if (DEBUG_LOCKS_WARN_ON(!depth && (hlock->prev_chain_key != 0)))
-		return 0;
-
-	curr->curr_chain_key = hlock->prev_chain_key;
-
-	lock_release_holdtime(hlock);
-
-#ifdef CONFIG_DEBUG_LOCKDEP
-	hlock->prev_chain_key = 0;
-	hlock->class = NULL;
-	hlock->acquire_ip = 0;
-	hlock->irq_context = 0;
-#endif
-	return 1;
-}
-
-/*
- * Remove the lock to the list of currently held locks - this gets
- * called on mutex_unlock()/spin_unlock*() (or on a failed
- * mutex_lock_interruptible()). This is done for unlocks that nest
- * perfectly. (i.e. the current top of the lock-stack is unlocked)
- */
-static void
-__lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
-{
-	struct task_struct *curr = current;
-
-	if (!check_unlock(curr, lock, ip))
-		return;
-
-	if (nested) {
-		if (!lock_release_nested(curr, lock, ip))
-			return;
-	} else {
-		if (!lock_release_non_nested(curr, lock, ip))
-			return;
-	}
-
-	check_chain_key(curr);
-}
-
-/*
- * Check whether we follow the irq-flags state precisely:
- */
-static void check_flags(unsigned long flags)
-{
-#if defined(CONFIG_DEBUG_LOCKDEP) && defined(CONFIG_TRACE_IRQFLAGS)
-	if (!debug_locks)
-		return;
-
-	if (irqs_disabled_flags(flags))
-		DEBUG_LOCKS_WARN_ON(current->hardirqs_enabled);
-	else
-		DEBUG_LOCKS_WARN_ON(!current->hardirqs_enabled);
-
-	/*
-	 * We dont accurately track softirq state in e.g.
-	 * hardirq contexts (such as on 4KSTACKS), so only
-	 * check if not in hardirq contexts:
-	 */
-	if (!hardirq_count()) {
-		if (softirq_count())
-			DEBUG_LOCKS_WARN_ON(current->softirqs_enabled);
-		else
-			DEBUG_LOCKS_WARN_ON(!current->softirqs_enabled);
-	}
-
-	if (!debug_locks)
-		print_irqtrace_events(current);
-#endif
-}
-
-/*
- * We are not always called with irqs disabled - do that here,
- * and also avoid lockdep recursion:
- */
-void lock_acquire(struct lockdep_map *lock, unsigned int subclass,
-		  int trylock, int read, int check, unsigned long ip)
-{
-	unsigned long flags;
-
-	if (unlikely(!lock_stat && !prove_locking))
-		return;
-
-	if (unlikely(current->lockdep_recursion))
-		return;
-
-	raw_local_irq_save(flags);
-	check_flags(flags);
-
-	current->lockdep_recursion = 1;
-	__lock_acquire(lock, subclass, trylock, read, check,
-		       irqs_disabled_flags(flags), ip);
-	current->lockdep_recursion = 0;
-	raw_local_irq_restore(flags);
-}
-
-EXPORT_SYMBOL_GPL(lock_acquire);
-
-void lock_release(struct lockdep_map *lock, int nested, unsigned long ip)
-{
-	unsigned long flags;
-
-	if (unlikely(!lock_stat && !prove_locking))
-		return;
-
-	if (unlikely(current->lockdep_recursion))
-		return;
-
-	raw_local_irq_save(flags);
-	check_flags(flags);
-	current->lockdep_recursion = 1;
-	__lock_release(lock, nested, ip);
-	current->lockdep_recursion = 0;
-	raw_local_irq_restore(flags);
-}
-
-EXPORT_SYMBOL_GPL(lock_release);
-
-#ifdef CONFIG_LOCK_STAT
-static int
-print_lock_contention_bug(struct task_struct *curr, struct lockdep_map *lock,
-			   unsigned long ip)
-{
-	if (!debug_locks_off())
-		return 0;
-	if (debug_locks_silent)
-		return 0;
-
-	printk("\n=================================\n");
-	printk(  "[ BUG: bad contention detected! ]\n");
-	printk(  "---------------------------------\n");
-	printk("%s/%d is trying to contend lock (",
-		curr->comm, task_pid_nr(curr));
-	print_lockdep_cache(lock);
-	printk(") at:\n");
-	print_ip_sym(ip);
-	printk("but there are no locks held!\n");
-	printk("\nother info that might help us debug this:\n");
-	lockdep_print_held_locks(curr);
-
-	printk("\nstack backtrace:\n");
-	dump_stack();
-
-	return 0;
-}
-
-static void
-__lock_contended(struct lockdep_map *lock, unsigned long ip)
-{
-	struct task_struct *curr = current;
-	struct held_lock *hlock, *prev_hlock;
-	struct lock_class_stats *stats;
-	unsigned int depth;
-	int i, point;
-
-	depth = curr->lockdep_depth;
-	if (DEBUG_LOCKS_WARN_ON(!depth))
-		return;
-
-	prev_hlock = NULL;
-	for (i = depth-1; i >= 0; i--) {
-		hlock = curr->held_locks + i;
-		/*
-		 * We must not cross into another context:
-		 */
-		if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
-			break;
-		if (hlock->instance == lock)
-			goto found_it;
-		prev_hlock = hlock;
-	}
-	print_lock_contention_bug(curr, lock, ip);
-	return;
-
-found_it:
-	hlock->waittime_stamp = sched_clock();
-
-	point = lock_contention_point(hlock->class, ip);
-
-	stats = get_lock_stats(hlock->class);
-	if (point < ARRAY_SIZE(stats->contention_point))
-		stats->contention_point[i]++;
-	if (lock->cpu != smp_processor_id())
-		stats->bounces[bounce_contended + !!hlock->read]++;
-	put_lock_stats(stats);
-}
-
-static void
-__lock_acquired(struct lockdep_map *lock)
-{
-	struct task_struct *curr = current;
-	struct held_lock *hlock, *prev_hlock;
-	struct lock_class_stats *stats;
-	unsigned int depth;
-	u64 now;
-	s64 waittime = 0;
-	int i, cpu;
-
-	depth = curr->lockdep_depth;
-	if (DEBUG_LOCKS_WARN_ON(!depth))
-		return;
-
-	prev_hlock = NULL;
-	for (i = depth-1; i >= 0; i--) {
-		hlock = curr->held_locks + i;
-		/*
-		 * We must not cross into another context:
-		 */
-		if (prev_hlock && prev_hlock->irq_context != hlock->irq_context)
-			break;
-		if (hlock->instance == lock)
-			goto found_it;
-		prev_hlock = hlock;
-	}
-	print_lock_contention_bug(curr, lock, _RET_IP_);
-	return;
-
-found_it:
-	cpu = smp_processor_id();
-	if (hlock->waittime_stamp) {
-		now = sched_clock();
-		waittime = now - hlock->waittime_stamp;
-		hlock->holdtime_stamp = now;
-	}
-
-	stats = get_lock_stats(hlock->class);
-	if (waittime) {
-		if (hlock->read)
-			lock_time_inc(&stats->read_waittime, waittime);
-		else
-			lock_time_inc(&stats->write_waittime, waittime);
-	}
-	if (lock->cpu != cpu)
-		stats->bounces[bounce_acquired + !!hlock->read]++;
-	put_lock_stats(stats);
-
-	lock->cpu = cpu;
-}
-
-void lock_contended(struct lockdep_map *lock, unsigned long ip)
-{
-	unsigned long flags;
-
-	if (unlikely(!lock_stat))
-		return;
-
-	if (unlikely(current->lockdep_recursion))
-		return;
-
-	raw_local_irq_save(flags);
-	check_flags(flags);
-	current->lockdep_recursion = 1;
-	__lock_contended(lock, ip);
-	current->lockdep_recursion = 0;
-	raw_local_irq_restore(flags);
-}
-EXPORT_SYMBOL_GPL(lock_contended);
-
-void lock_acquired(struct lockdep_map *lock)
-{
-	unsigned long flags;
-
-	if (unlikely(!lock_stat))
-		return;
-
-	if (unlikely(current->lockdep_recursion))
-		return;
-
-	raw_local_irq_save(flags);
-	check_flags(flags);
-	current->lockdep_recursion = 1;
-	__lock_acquired(lock);
-	current->lockdep_recursion = 0;
-	raw_local_irq_restore(flags);
-}
-EXPORT_SYMBOL_GPL(lock_acquired);
-#endif
-
-/*
- * Used by the testsuite, sanitize the validator state
- * after a simulated failure:
- */
-
-void lockdep_reset(void)
-{
-	unsigned long flags;
-	int i;
-
-	raw_local_irq_save(flags);
-	current->curr_chain_key = 0;
-	current->lockdep_depth = 0;
-	current->lockdep_recursion = 0;
-	memset(current->held_locks, 0, MAX_LOCK_DEPTH*sizeof(struct held_lock));
-	nr_hardirq_chains = 0;
-	nr_softirq_chains = 0;
-	nr_process_chains = 0;
-	debug_locks = 1;
-	for (i = 0; i < CHAINHASH_SIZE; i++)
-		INIT_LIST_HEAD(chainhash_table + i);
-	raw_local_irq_restore(flags);
-}
-
-static void zap_class(struct lock_class *class)
-{
-	int i;
-
-	/*
-	 * Remove all dependencies this lock is
-	 * involved in:
-	 */
-	for (i = 0; i < nr_list_entries; i++) {
-		if (list_entries[i].class == class)
-			list_del_rcu(&list_entries[i].entry);
-	}
-	/*
-	 * Unhash the class and remove it from the all_lock_classes list:
-	 */
-	list_del_rcu(&class->hash_entry);
-	list_del_rcu(&class->lock_entry);
-
-}
-
-static inline int within(void *addr, void *start, unsigned long size)
-{
-	return addr >= start && addr < start + size;
-}
-
-void lockdep_free_key_range(void *start, unsigned long size)
-{
-	struct lock_class *class, *next;
-	struct list_head *head;
-	unsigned long flags;
-	int i;
-
-	raw_local_irq_save(flags);
-	graph_lock();
-
-	/*
-	 * Unhash all classes that were created by this module:
-	 */
-	for (i = 0; i < CLASSHASH_SIZE; i++) {
-		head = classhash_table + i;
-		if (list_empty(head))
-			continue;
-		list_for_each_entry_safe(class, next, head, hash_entry)
-			if (within(class->key, start, size))
-				zap_class(class);
-	}
-
-	graph_unlock();
-	raw_local_irq_restore(flags);
-}
-
-void lockdep_reset_lock(struct lockdep_map *lock)
-{
-	struct lock_class *class, *next;
-	struct list_head *head;
-	unsigned long flags;
-	int i, j;
-
-	raw_local_irq_save(flags);
-
-	/*
-	 * Remove all classes this lock might have:
-	 */
-	for (j = 0; j < MAX_LOCKDEP_SUBCLASSES; j++) {
-		/*
-		 * If the class exists we look it up and zap it:
-		 */
-		class = look_up_lock_class(lock, j);
-		if (class)
-			zap_class(class);
-	}
-	/*
-	 * Debug check: in the end all mapped classes should
-	 * be gone.
-	 */
-	graph_lock();
-	for (i = 0; i < CLASSHASH_SIZE; i++) {
-		head = classhash_table + i;
-		if (list_empty(head))
-			continue;
-		list_for_each_entry_safe(class, next, head, hash_entry) {
-			if (unlikely(class == lock->class_cache)) {
-				if (debug_locks_off_graph_unlock())
-					WARN_ON(1);
-				goto out_restore;
-			}
-		}
-	}
-	graph_unlock();
-
-out_restore:
-	raw_local_irq_restore(flags);
-}
-
-void lockdep_init(void)
-{
-	int i;
-
-	/*
-	 * Some architectures have their own start_kernel()
-	 * code which calls lockdep_init(), while we also
-	 * call lockdep_init() from the start_kernel() itself,
-	 * and we want to initialize the hashes only once:
-	 */
-	if (lockdep_initialized)
-		return;
-
-	for (i = 0; i < CLASSHASH_SIZE; i++)
-		INIT_LIST_HEAD(classhash_table + i);
-
-	for (i = 0; i < CHAINHASH_SIZE; i++)
-		INIT_LIST_HEAD(chainhash_table + i);
-
-	lockdep_initialized = 1;
-}
-
-void __init lockdep_info(void)
-{
-	printk("Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar\n");
-
-	printk("... MAX_LOCKDEP_SUBCLASSES:    %lu\n", MAX_LOCKDEP_SUBCLASSES);
-	printk("... MAX_LOCK_DEPTH:          %lu\n", MAX_LOCK_DEPTH);
-	printk("... MAX_LOCKDEP_KEYS:        %lu\n", MAX_LOCKDEP_KEYS);
-	printk("... CLASSHASH_SIZE:           %lu\n", CLASSHASH_SIZE);
-	printk("... MAX_LOCKDEP_ENTRIES:     %lu\n", MAX_LOCKDEP_ENTRIES);
-	printk("... MAX_LOCKDEP_CHAINS:      %lu\n", MAX_LOCKDEP_CHAINS);
-	printk("... CHAINHASH_SIZE:          %lu\n", CHAINHASH_SIZE);
-
-	printk(" memory used by lock dependency info: %lu kB\n",
-		(sizeof(struct lock_class) * MAX_LOCKDEP_KEYS +
-		sizeof(struct list_head) * CLASSHASH_SIZE +
-		sizeof(struct lock_list) * MAX_LOCKDEP_ENTRIES +
-		sizeof(struct lock_chain) * MAX_LOCKDEP_CHAINS +
-		sizeof(struct list_head) * CHAINHASH_SIZE) / 1024);
-
-	printk(" per task-struct memory footprint: %lu bytes\n",
-		sizeof(struct held_lock) * MAX_LOCK_DEPTH);
-
-#ifdef CONFIG_DEBUG_LOCKDEP
-	if (lockdep_init_error) {
-		printk("WARNING: lockdep init error! Arch code didn't call lockdep_init() early enough?\n");
-		printk("Call stack leading to lockdep invocation was:\n");
-		print_stack_trace(&lockdep_init_trace, 0);
-	}
-#endif
-}
-
-static inline int in_range(const void *start, const void *addr, const void *end)
-{
-	return addr >= start && addr <= end;
-}
-
-static void
-print_freed_lock_bug(struct task_struct *curr, const void *mem_from,
-		     const void *mem_to, struct held_lock *hlock)
-{
-	if (!debug_locks_off())
-		return;
-	if (debug_locks_silent)
-		return;
-
-	printk("\n=========================\n");
-	printk(  "[ BUG: held lock freed! ]\n");
-	printk(  "-------------------------\n");
-	printk("%s/%d is freeing memory %p-%p, with a lock still held there!\n",
-		curr->comm, task_pid_nr(curr), mem_from, mem_to-1);
-	print_lock(hlock);
-	lockdep_print_held_locks(curr);
-
-	printk("\nstack backtrace:\n");
-	dump_stack();
-}
-
-/*
- * Called when kernel memory is freed (or unmapped), or if a lock
- * is destroyed or reinitialized - this code checks whether there is
- * any held lock in the memory range of <from> to <to>:
- */
-void debug_check_no_locks_freed(const void *mem_from, unsigned long mem_len)
-{
-	const void *mem_to = mem_from + mem_len, *lock_from, *lock_to;
-	struct task_struct *curr = current;
-	struct held_lock *hlock;
-	unsigned long flags;
-	int i;
-
-	if (unlikely(!debug_locks))
-		return;
-
-	local_irq_save(flags);
-	for (i = 0; i < curr->lockdep_depth; i++) {
-		hlock = curr->held_locks + i;
-
-		lock_from = (void *)hlock->instance;
-		lock_to = (void *)(hlock->instance + 1);
-
-		if (!in_range(mem_from, lock_from, mem_to) &&
-					!in_range(mem_from, lock_to, mem_to))
-			continue;
-
-		print_freed_lock_bug(curr, mem_from, mem_to, hlock);
-		break;
-	}
-	local_irq_restore(flags);
-}
-EXPORT_SYMBOL_GPL(debug_check_no_locks_freed);
-
-static void print_held_locks_bug(struct task_struct *curr)
-{
-	if (!debug_locks_off())
-		return;
-	if (debug_locks_silent)
-		return;
-
-	printk("\n=====================================\n");
-	printk(  "[ BUG: lock held at task exit time! ]\n");
-	printk(  "-------------------------------------\n");
-	printk("%s/%d is exiting with locks still held!\n",
-		curr->comm, task_pid_nr(curr));
-	lockdep_print_held_locks(curr);
-
-	printk("\nstack backtrace:\n");
-	dump_stack();
-}
-
-void debug_check_no_locks_held(struct task_struct *task)
-{
-	if (unlikely(task->lockdep_depth > 0))
-		print_held_locks_bug(task);
-}
-
-void debug_show_all_locks(void)
-{
-	struct task_struct *g, *p;
-	int count = 10;
-	int unlock = 1;
-
-	if (unlikely(!debug_locks)) {
-		printk("INFO: lockdep is turned off.\n");
-		return;
-	}
-	printk("\nShowing all locks held in the system:\n");
-
-	/*
-	 * Here we try to get the tasklist_lock as hard as possible,
-	 * if not successful after 2 seconds we ignore it (but keep
-	 * trying). This is to enable a debug printout even if a
-	 * tasklist_lock-holding task deadlocks or crashes.
-	 */
-retry:
-	if (!read_trylock(&tasklist_lock)) {
-		if (count == 10)
-			printk("hm, tasklist_lock locked, retrying... ");
-		if (count) {
-			count--;
-			printk(" #%d", 10-count);
-			mdelay(200);
-			goto retry;
-		}
-		printk(" ignoring it.\n");
-		unlock = 0;
-	}
-	if (count != 10)
-		printk(" locked it.\n");
-
-	do_each_thread(g, p) {
-		if (p->lockdep_depth)
-			lockdep_print_held_locks(p);
-		if (!unlock)
-			if (read_trylock(&tasklist_lock))
-				unlock = 1;
-	} while_each_thread(g, p);
-
-	printk("\n");
-	printk("=============================================\n\n");
-
-	if (unlock)
-		read_unlock(&tasklist_lock);
-}
-
-EXPORT_SYMBOL_GPL(debug_show_all_locks);
-
-void debug_show_held_locks(struct task_struct *task)
-{
-	if (unlikely(!debug_locks)) {
-		printk("INFO: lockdep is turned off.\n");
-		return;
-	}
-	lockdep_print_held_locks(task);
-}
-
-EXPORT_SYMBOL_GPL(debug_show_held_locks);
-
-void lockdep_sys_exit(void)
-{
-	struct task_struct *curr = current;
-
-	if (unlikely(curr->lockdep_depth)) {
-		if (!debug_locks_off())
-			return;
-		printk("\n================================================\n");
-		printk(  "[ BUG: lock held when returning to user space! ]\n");
-		printk(  "------------------------------------------------\n");
-		printk("%s/%d is leaving the kernel with locks still held!\n",
-				curr->comm, curr->pid);
-		lockdep_print_held_locks(curr);
-	}
-}
Index: linux-2.6-lttng.stable/kernel/Makefile
===================================================================
--- linux-2.6-lttng.stable.orig/kernel/Makefile	2007-10-29 09:52:13.000000000 -0400
+++ linux-2.6-lttng.stable/kernel/Makefile	2007-10-29 09:52:35.000000000 -0400
@@ -15,10 +15,6 @@ obj-$(CONFIG_SYSCTL) += sysctl_check.o
 obj-$(CONFIG_STACKTRACE) += stacktrace.o
 obj-y += time/
 obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
-obj-$(CONFIG_LOCKDEP) += lockdep.o
-ifeq ($(CONFIG_PROC_FS),y)
-obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
-endif
 obj-$(CONFIG_FUTEX) += futex.o
 ifeq ($(CONFIG_COMPAT),y)
 obj-$(CONFIG_FUTEX) += futex_compat.o
Index: linux-2.6-lttng.stable/instrumentation/lockdep_internals.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-lttng.stable/instrumentation/lockdep_internals.h	2007-10-29 09:52:35.000000000 -0400
@@ -0,0 +1,78 @@
+/*
+ * kernel/lockdep_internals.h
+ *
+ * Runtime locking correctness validator
+ *
+ * lockdep subsystem internal functions and variables.
+ */
+
+/*
+ * MAX_LOCKDEP_ENTRIES is the maximum number of lock dependencies
+ * we track.
+ *
+ * We use the per-lock dependency maps in two ways: we grow it by adding
+ * every to-be-taken lock to all currently held lock's own dependency
+ * table (if it's not there yet), and we check it for lock order
+ * conflicts and deadlocks.
+ */
+#define MAX_LOCKDEP_ENTRIES	8192UL
+
+#define MAX_LOCKDEP_KEYS_BITS	11
+#define MAX_LOCKDEP_KEYS	(1UL << MAX_LOCKDEP_KEYS_BITS)
+
+#define MAX_LOCKDEP_CHAINS_BITS	14
+#define MAX_LOCKDEP_CHAINS	(1UL << MAX_LOCKDEP_CHAINS_BITS)
+
+/*
+ * Stack-trace: tightly packed array of stack backtrace
+ * addresses. Protected by the hash_lock.
+ */
+#define MAX_STACK_TRACE_ENTRIES	262144UL
+
+extern struct list_head all_lock_classes;
+
+extern void
+get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4);
+
+extern const char * __get_key_name(struct lockdep_subclass_key *key, char *str);
+
+extern unsigned long nr_lock_classes;
+extern unsigned long nr_list_entries;
+extern unsigned long nr_lock_chains;
+extern unsigned long nr_stack_trace_entries;
+
+extern unsigned int nr_hardirq_chains;
+extern unsigned int nr_softirq_chains;
+extern unsigned int nr_process_chains;
+extern unsigned int max_lockdep_depth;
+extern unsigned int max_recursion_depth;
+
+#ifdef CONFIG_DEBUG_LOCKDEP
+/*
+ * Various lockdep statistics:
+ */
+extern atomic_t chain_lookup_hits;
+extern atomic_t chain_lookup_misses;
+extern atomic_t hardirqs_on_events;
+extern atomic_t hardirqs_off_events;
+extern atomic_t redundant_hardirqs_on;
+extern atomic_t redundant_hardirqs_off;
+extern atomic_t softirqs_on_events;
+extern atomic_t softirqs_off_events;
+extern atomic_t redundant_softirqs_on;
+extern atomic_t redundant_softirqs_off;
+extern atomic_t nr_unused_locks;
+extern atomic_t nr_cyclic_checks;
+extern atomic_t nr_cyclic_check_recursions;
+extern atomic_t nr_find_usage_forwards_checks;
+extern atomic_t nr_find_usage_forwards_recursions;
+extern atomic_t nr_find_usage_backwards_checks;
+extern atomic_t nr_find_usage_backwards_recursions;
+# define debug_atomic_inc(ptr)		atomic_inc(ptr)
+# define debug_atomic_dec(ptr)		atomic_dec(ptr)
+# define debug_atomic_read(ptr)		atomic_read(ptr)
+#else
+# define debug_atomic_inc(ptr)		do { } while (0)
+# define debug_atomic_dec(ptr)		do { } while (0)
+# define debug_atomic_read(ptr)		0
+#endif
Index: linux-2.6-lttng.stable/instrumentation/lockdep_proc.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-lttng.stable/instrumentation/lockdep_proc.c	2007-10-29 09:52:35.000000000 -0400
@@ -0,0 +1,683 @@
+/*
+ * kernel/lockdep_proc.c
+ *
+ * Runtime locking correctness validator
+ *
+ * Started by Ingo Molnar:
+ *
+ *  Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@xxxxxxxxxx>
+ *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@xxxxxxxxxx>
+ *
+ * Code for /proc/lockdep and /proc/lockdep_stats:
+ *
+ */
+#include <linux/module.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/kallsyms.h>
+#include <linux/debug_locks.h>
+#include <linux/vmalloc.h>
+#include <linux/sort.h>
+#include <asm/uaccess.h>
+#include <asm/div64.h>
+
+#include "lockdep_internals.h"
+
+static void *l_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct lock_class *class;
+
+	(*pos)++;
+
+	if (v == SEQ_START_TOKEN)
+		class = m->private;
+	else {
+		class = v;
+
+		if (class->lock_entry.next != &all_lock_classes)
+			class = list_entry(class->lock_entry.next,
+					   struct lock_class, lock_entry);
+		else
+			class = NULL;
+	}
+
+	return class;
+}
+
+static void *l_start(struct seq_file *m, loff_t *pos)
+{
+	struct lock_class *class;
+	loff_t i = 0;
+
+	if (*pos == 0)
+		return SEQ_START_TOKEN;
+
+	list_for_each_entry(class, &all_lock_classes, lock_entry) {
+		if (++i == *pos)
+		return class;
+	}
+	return NULL;
+}
+
+static void l_stop(struct seq_file *m, void *v)
+{
+}
+
+static unsigned long count_forward_deps(struct lock_class *class)
+{
+	struct lock_list *entry;
+	unsigned long ret = 1;
+
+	/*
+	 * Recurse this class's dependency list:
+	 */
+	list_for_each_entry(entry, &class->locks_after, entry)
+		ret += count_forward_deps(entry->class);
+
+	return ret;
+}
+
+static unsigned long count_backward_deps(struct lock_class *class)
+{
+	struct lock_list *entry;
+	unsigned long ret = 1;
+
+	/*
+	 * Recurse this class's dependency list:
+	 */
+	list_for_each_entry(entry, &class->locks_before, entry)
+		ret += count_backward_deps(entry->class);
+
+	return ret;
+}
+
+static void print_name(struct seq_file *m, struct lock_class *class)
+{
+	char str[128];
+	const char *name = class->name;
+
+	if (!name) {
+		name = __get_key_name(class->key, str);
+		seq_printf(m, "%s", name);
+	} else{
+		seq_printf(m, "%s", name);
+		if (class->name_version > 1)
+			seq_printf(m, "#%d", class->name_version);
+		if (class->subclass)
+			seq_printf(m, "/%d", class->subclass);
+	}
+}
+
+static int l_show(struct seq_file *m, void *v)
+{
+	unsigned long nr_forward_deps, nr_backward_deps;
+	struct lock_class *class = v;
+	struct lock_list *entry;
+	char c1, c2, c3, c4;
+
+	if (v == SEQ_START_TOKEN) {
+		seq_printf(m, "all lock classes:\n");
+		return 0;
+	}
+
+	seq_printf(m, "%p", class->key);
+#ifdef CONFIG_DEBUG_LOCKDEP
+	seq_printf(m, " OPS:%8ld", class->ops);
+#endif
+	nr_forward_deps = count_forward_deps(class);
+	seq_printf(m, " FD:%5ld", nr_forward_deps);
+
+	nr_backward_deps = count_backward_deps(class);
+	seq_printf(m, " BD:%5ld", nr_backward_deps);
+
+	get_usage_chars(class, &c1, &c2, &c3, &c4);
+	seq_printf(m, " %c%c%c%c", c1, c2, c3, c4);
+
+	seq_printf(m, ": ");
+	print_name(m, class);
+	seq_puts(m, "\n");
+
+	list_for_each_entry(entry, &class->locks_after, entry) {
+		if (entry->distance == 1) {
+			seq_printf(m, " -> [%p] ", entry->class);
+			print_name(m, entry->class);
+			seq_puts(m, "\n");
+		}
+	}
+	seq_puts(m, "\n");
+
+	return 0;
+}
+
+static const struct seq_operations lockdep_ops = {
+	.start	= l_start,
+	.next	= l_next,
+	.stop	= l_stop,
+	.show	= l_show,
+};
+
+static int lockdep_open(struct inode *inode, struct file *file)
+{
+	int res = seq_open(file, &lockdep_ops);
+	if (!res) {
+		struct seq_file *m = file->private_data;
+
+		if (!list_empty(&all_lock_classes))
+			m->private = list_entry(all_lock_classes.next,
+					struct lock_class, lock_entry);
+		else
+			m->private = NULL;
+	}
+	return res;
+}
+
+static const struct file_operations proc_lockdep_operations = {
+	.open		= lockdep_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= seq_release,
+};
+
+static void lockdep_stats_debug_show(struct seq_file *m)
+{
+#ifdef CONFIG_DEBUG_LOCKDEP
+	unsigned int hi1 = debug_atomic_read(&hardirqs_on_events),
+		     hi2 = debug_atomic_read(&hardirqs_off_events),
+		     hr1 = debug_atomic_read(&redundant_hardirqs_on),
+		     hr2 = debug_atomic_read(&redundant_hardirqs_off),
+		     si1 = debug_atomic_read(&softirqs_on_events),
+		     si2 = debug_atomic_read(&softirqs_off_events),
+		     sr1 = debug_atomic_read(&redundant_softirqs_on),
+		     sr2 = debug_atomic_read(&redundant_softirqs_off);
+
+	seq_printf(m, " chain lookup misses:           %11u\n",
+		debug_atomic_read(&chain_lookup_misses));
+	seq_printf(m, " chain lookup hits:             %11u\n",
+		debug_atomic_read(&chain_lookup_hits));
+	seq_printf(m, " cyclic checks:                 %11u\n",
+		debug_atomic_read(&nr_cyclic_checks));
+	seq_printf(m, " cyclic-check recursions:       %11u\n",
+		debug_atomic_read(&nr_cyclic_check_recursions));
+	seq_printf(m, " find-mask forwards checks:     %11u\n",
+		debug_atomic_read(&nr_find_usage_forwards_checks));
+	seq_printf(m, " find-mask forwards recursions: %11u\n",
+		debug_atomic_read(&nr_find_usage_forwards_recursions));
+	seq_printf(m, " find-mask backwards checks:    %11u\n",
+		debug_atomic_read(&nr_find_usage_backwards_checks));
+	seq_printf(m, " find-mask backwards recursions:%11u\n",
+		debug_atomic_read(&nr_find_usage_backwards_recursions));
+
+	seq_printf(m, " hardirq on events:             %11u\n", hi1);
+	seq_printf(m, " hardirq off events:            %11u\n", hi2);
+	seq_printf(m, " redundant hardirq ons:         %11u\n", hr1);
+	seq_printf(m, " redundant hardirq offs:        %11u\n", hr2);
+	seq_printf(m, " softirq on events:             %11u\n", si1);
+	seq_printf(m, " softirq off events:            %11u\n", si2);
+	seq_printf(m, " redundant softirq ons:         %11u\n", sr1);
+	seq_printf(m, " redundant softirq offs:        %11u\n", sr2);
+#endif
+}
+
+static int lockdep_stats_show(struct seq_file *m, void *v)
+{
+	struct lock_class *class;
+	unsigned long nr_unused = 0, nr_uncategorized = 0,
+		      nr_irq_safe = 0, nr_irq_unsafe = 0,
+		      nr_softirq_safe = 0, nr_softirq_unsafe = 0,
+		      nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
+		      nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
+		      nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
+		      nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
+		      sum_forward_deps = 0, factor = 0;
+
+	list_for_each_entry(class, &all_lock_classes, lock_entry) {
+
+		if (class->usage_mask == 0)
+			nr_unused++;
+		if (class->usage_mask == LOCKF_USED)
+			nr_uncategorized++;
+		if (class->usage_mask & LOCKF_USED_IN_IRQ)
+			nr_irq_safe++;
+		if (class->usage_mask & LOCKF_ENABLED_IRQS)
+			nr_irq_unsafe++;
+		if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
+			nr_softirq_safe++;
+		if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
+			nr_softirq_unsafe++;
+		if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
+			nr_hardirq_safe++;
+		if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
+			nr_hardirq_unsafe++;
+		if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
+			nr_irq_read_safe++;
+		if (class->usage_mask & LOCKF_ENABLED_IRQS_READ)
+			nr_irq_read_unsafe++;
+		if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
+			nr_softirq_read_safe++;
+		if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
+			nr_softirq_read_unsafe++;
+		if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
+			nr_hardirq_read_safe++;
+		if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
+			nr_hardirq_read_unsafe++;
+
+		sum_forward_deps += count_forward_deps(class);
+	}
+#ifdef CONFIG_DEBUG_LOCKDEP
+	DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused);
+#endif
+	seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
+			nr_lock_classes, MAX_LOCKDEP_KEYS);
+	seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
+			nr_list_entries, MAX_LOCKDEP_ENTRIES);
+	seq_printf(m, " indirect dependencies:         %11lu\n",
+			sum_forward_deps);
+
+	/*
+	 * Total number of dependencies:
+	 *
+	 * All irq-safe locks may nest inside irq-unsafe locks,
+	 * plus all the other known dependencies:
+	 */
+	seq_printf(m, " all direct dependencies:       %11lu\n",
+			nr_irq_unsafe * nr_irq_safe +
+			nr_hardirq_unsafe * nr_hardirq_safe +
+			nr_list_entries);
+
+	/*
+	 * Estimated factor between direct and indirect
+	 * dependencies:
+	 */
+	if (nr_list_entries)
+		factor = sum_forward_deps / nr_list_entries;
+
+#ifdef CONFIG_PROVE_LOCKING
+	seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
+			nr_lock_chains, MAX_LOCKDEP_CHAINS);
+#endif
+
+#ifdef CONFIG_TRACE_IRQFLAGS
+	seq_printf(m, " in-hardirq chains:             %11u\n",
+			nr_hardirq_chains);
+	seq_printf(m, " in-softirq chains:             %11u\n",
+			nr_softirq_chains);
+#endif
+	seq_printf(m, " in-process chains:             %11u\n",
+			nr_process_chains);
+	seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
+			nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
+	seq_printf(m, " combined max dependencies:     %11u\n",
+			(nr_hardirq_chains + 1) *
+			(nr_softirq_chains + 1) *
+			(nr_process_chains + 1)
+	);
+	seq_printf(m, " hardirq-safe locks:            %11lu\n",
+			nr_hardirq_safe);
+	seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
+			nr_hardirq_unsafe);
+	seq_printf(m, " softirq-safe locks:            %11lu\n",
+			nr_softirq_safe);
+	seq_printf(m, " softirq-unsafe locks:          %11lu\n",
+			nr_softirq_unsafe);
+	seq_printf(m, " irq-safe locks:                %11lu\n",
+			nr_irq_safe);
+	seq_printf(m, " irq-unsafe locks:              %11lu\n",
+			nr_irq_unsafe);
+
+	seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
+			nr_hardirq_read_safe);
+	seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
+			nr_hardirq_read_unsafe);
+	seq_printf(m, " softirq-read-safe locks:       %11lu\n",
+			nr_softirq_read_safe);
+	seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
+			nr_softirq_read_unsafe);
+	seq_printf(m, " irq-read-safe locks:           %11lu\n",
+			nr_irq_read_safe);
+	seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
+			nr_irq_read_unsafe);
+
+	seq_printf(m, " uncategorized locks:           %11lu\n",
+			nr_uncategorized);
+	seq_printf(m, " unused locks:                  %11lu\n",
+			nr_unused);
+	seq_printf(m, " max locking depth:             %11u\n",
+			max_lockdep_depth);
+	seq_printf(m, " max recursion depth:           %11u\n",
+			max_recursion_depth);
+	lockdep_stats_debug_show(m);
+	seq_printf(m, " debug_locks:                   %11u\n",
+			debug_locks);
+
+	return 0;
+}
+
+static int lockdep_stats_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, lockdep_stats_show, NULL);
+}
+
+static const struct file_operations proc_lockdep_stats_operations = {
+	.open		= lockdep_stats_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+#ifdef CONFIG_LOCK_STAT
+
+struct lock_stat_data {
+	struct lock_class *class;
+	struct lock_class_stats stats;
+};
+
+struct lock_stat_seq {
+	struct lock_stat_data *iter;
+	struct lock_stat_data *iter_end;
+	struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
+};
+
+/*
+ * sort on absolute number of contentions
+ */
+static int lock_stat_cmp(const void *l, const void *r)
+{
+	const struct lock_stat_data *dl = l, *dr = r;
+	unsigned long nl, nr;
+
+	nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
+	nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
+
+	return nr - nl;
+}
+
+static void seq_line(struct seq_file *m, char c, int offset, int length)
+{
+	int i;
+
+	for (i = 0; i < offset; i++)
+		seq_puts(m, " ");
+	for (i = 0; i < length; i++)
+		seq_printf(m, "%c", c);
+	seq_puts(m, "\n");
+}
+
+static void snprint_time(char *buf, size_t bufsiz, s64 nr)
+{
+	unsigned long rem;
+
+	rem = do_div(nr, 1000); /* XXX: do_div_signed */
+	snprintf(buf, bufsiz, "%lld.%02d", (long long)nr, ((int)rem+5)/10);
+}
+
+static void seq_time(struct seq_file *m, s64 time)
+{
+	char num[15];
+
+	snprint_time(num, sizeof(num), time);
+	seq_printf(m, " %14s", num);
+}
+
+static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
+{
+	seq_printf(m, "%14lu", lt->nr);
+	seq_time(m, lt->min);
+	seq_time(m, lt->max);
+	seq_time(m, lt->total);
+}
+
+static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
+{
+	char name[39];
+	struct lock_class *class;
+	struct lock_class_stats *stats;
+	int i, namelen;
+
+	class = data->class;
+	stats = &data->stats;
+
+	namelen = 38;
+	if (class->name_version > 1)
+		namelen -= 2; /* XXX truncates versions > 9 */
+	if (class->subclass)
+		namelen -= 2;
+
+	if (!class->name) {
+		char str[KSYM_NAME_LEN];
+		const char *key_name;
+
+		key_name = __get_key_name(class->key, str);
+		snprintf(name, namelen, "%s", key_name);
+	} else {
+		snprintf(name, namelen, "%s", class->name);
+	}
+	namelen = strlen(name);
+	if (class->name_version > 1) {
+		snprintf(name+namelen, 3, "#%d", class->name_version);
+		namelen += 2;
+	}
+	if (class->subclass) {
+		snprintf(name+namelen, 3, "/%d", class->subclass);
+		namelen += 2;
+	}
+
+	if (stats->write_holdtime.nr) {
+		if (stats->read_holdtime.nr)
+			seq_printf(m, "%38s-W:", name);
+		else
+			seq_printf(m, "%40s:", name);
+
+		seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
+		seq_lock_time(m, &stats->write_waittime);
+		seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
+		seq_lock_time(m, &stats->write_holdtime);
+		seq_puts(m, "\n");
+	}
+
+	if (stats->read_holdtime.nr) {
+		seq_printf(m, "%38s-R:", name);
+		seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
+		seq_lock_time(m, &stats->read_waittime);
+		seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
+		seq_lock_time(m, &stats->read_holdtime);
+		seq_puts(m, "\n");
+	}
+
+	if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
+		return;
+
+	if (stats->read_holdtime.nr)
+		namelen += 2;
+
+	for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) {
+		char sym[KSYM_SYMBOL_LEN];
+		char ip[32];
+
+		if (class->contention_point[i] == 0)
+			break;
+
+		if (!i)
+			seq_line(m, '-', 40-namelen, namelen);
+
+		sprint_symbol(sym, class->contention_point[i]);
+		snprintf(ip, sizeof(ip), "[<%p>]",
+				(void *)class->contention_point[i]);
+		seq_printf(m, "%40s %14lu %29s %s\n", name,
+				stats->contention_point[i],
+				ip, sym);
+	}
+	if (i) {
+		seq_puts(m, "\n");
+		seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
+		seq_puts(m, "\n");
+	}
+}
+
+static void seq_header(struct seq_file *m)
+{
+	seq_printf(m, "lock_stat version 0.2\n");
+	seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
+	seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
+			"%14s %14s\n",
+			"class name",
+			"con-bounces",
+			"contentions",
+			"waittime-min",
+			"waittime-max",
+			"waittime-total",
+			"acq-bounces",
+			"acquisitions",
+			"holdtime-min",
+			"holdtime-max",
+			"holdtime-total");
+	seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
+	seq_printf(m, "\n");
+}
+
+static void *ls_start(struct seq_file *m, loff_t *pos)
+{
+	struct lock_stat_seq *data = m->private;
+
+	if (*pos == 0)
+		return SEQ_START_TOKEN;
+
+	data->iter = data->stats + *pos;
+	if (data->iter >= data->iter_end)
+		data->iter = NULL;
+
+	return data->iter;
+}
+
+static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct lock_stat_seq *data = m->private;
+
+	(*pos)++;
+
+	if (v == SEQ_START_TOKEN)
+		data->iter = data->stats;
+	else {
+		data->iter = v;
+		data->iter++;
+	}
+
+	if (data->iter == data->iter_end)
+		data->iter = NULL;
+
+	return data->iter;
+}
+
+static void ls_stop(struct seq_file *m, void *v)
+{
+}
+
+static int ls_show(struct seq_file *m, void *v)
+{
+	if (v == SEQ_START_TOKEN)
+		seq_header(m);
+	else
+		seq_stats(m, v);
+
+	return 0;
+}
+
+static struct seq_operations lockstat_ops = {
+	.start	= ls_start,
+	.next	= ls_next,
+	.stop	= ls_stop,
+	.show	= ls_show,
+};
+
+static int lock_stat_open(struct inode *inode, struct file *file)
+{
+	int res;
+	struct lock_class *class;
+	struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
+
+	if (!data)
+		return -ENOMEM;
+
+	res = seq_open(file, &lockstat_ops);
+	if (!res) {
+		struct lock_stat_data *iter = data->stats;
+		struct seq_file *m = file->private_data;
+
+		data->iter = iter;
+		list_for_each_entry(class, &all_lock_classes, lock_entry) {
+			iter->class = class;
+			iter->stats = lock_stats(class);
+			iter++;
+		}
+		data->iter_end = iter;
+
+		sort(data->stats, data->iter_end - data->iter,
+				sizeof(struct lock_stat_data),
+				lock_stat_cmp, NULL);
+
+		m->private = data;
+	} else
+		vfree(data);
+
+	return res;
+}
+
+static ssize_t lock_stat_write(struct file *file, const char __user *buf,
+			       size_t count, loff_t *ppos)
+{
+	struct lock_class *class;
+	char c;
+
+	if (count) {
+		if (get_user(c, buf))
+			return -EFAULT;
+
+		if (c != '0')
+			return count;
+
+		list_for_each_entry(class, &all_lock_classes, lock_entry)
+			clear_lock_stats(class);
+	}
+	return count;
+}
+
+static int lock_stat_release(struct inode *inode, struct file *file)
+{
+	struct seq_file *seq = file->private_data;
+
+	vfree(seq->private);
+	seq->private = NULL;
+	return seq_release(inode, file);
+}
+
+static const struct file_operations proc_lock_stat_operations = {
+	.open		= lock_stat_open,
+	.write		= lock_stat_write,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= lock_stat_release,
+};
+#endif /* CONFIG_LOCK_STAT */
+
+static int __init lockdep_proc_init(void)
+{
+	struct proc_dir_entry *entry;
+
+	entry = create_proc_entry("lockdep", S_IRUSR, NULL);
+	if (entry)
+		entry->proc_fops = &proc_lockdep_operations;
+
+	entry = create_proc_entry("lockdep_stats", S_IRUSR, NULL);
+	if (entry)
+		entry->proc_fops = &proc_lockdep_stats_operations;
+
+#ifdef CONFIG_LOCK_STAT
+	entry = create_proc_entry("lock_stat", S_IRUSR, NULL);
+	if (entry)
+		entry->proc_fops = &proc_lock_stat_operations;
+#endif
+
+	return 0;
+}
+
+__initcall(lockdep_proc_init);
+
Index: linux-2.6-lttng.stable/kernel/lockdep_internals.h
===================================================================
--- linux-2.6-lttng.stable.orig/kernel/lockdep_internals.h	2007-10-29 09:51:06.000000000 -0400
+++ /dev/null	1970-01-01 00:00:00.000000000 +0000
@@ -1,78 +0,0 @@
-/*
- * kernel/lockdep_internals.h
- *
- * Runtime locking correctness validator
- *
- * lockdep subsystem internal functions and variables.
- */
-
-/*
- * MAX_LOCKDEP_ENTRIES is the maximum number of lock dependencies
- * we track.
- *
- * We use the per-lock dependency maps in two ways: we grow it by adding
- * every to-be-taken lock to all currently held lock's own dependency
- * table (if it's not there yet), and we check it for lock order
- * conflicts and deadlocks.
- */
-#define MAX_LOCKDEP_ENTRIES	8192UL
-
-#define MAX_LOCKDEP_KEYS_BITS	11
-#define MAX_LOCKDEP_KEYS	(1UL << MAX_LOCKDEP_KEYS_BITS)
-
-#define MAX_LOCKDEP_CHAINS_BITS	14
-#define MAX_LOCKDEP_CHAINS	(1UL << MAX_LOCKDEP_CHAINS_BITS)
-
-/*
- * Stack-trace: tightly packed array of stack backtrace
- * addresses. Protected by the hash_lock.
- */
-#define MAX_STACK_TRACE_ENTRIES	262144UL
-
-extern struct list_head all_lock_classes;
-
-extern void
-get_usage_chars(struct lock_class *class, char *c1, char *c2, char *c3, char *c4);
-
-extern const char * __get_key_name(struct lockdep_subclass_key *key, char *str);
-
-extern unsigned long nr_lock_classes;
-extern unsigned long nr_list_entries;
-extern unsigned long nr_lock_chains;
-extern unsigned long nr_stack_trace_entries;
-
-extern unsigned int nr_hardirq_chains;
-extern unsigned int nr_softirq_chains;
-extern unsigned int nr_process_chains;
-extern unsigned int max_lockdep_depth;
-extern unsigned int max_recursion_depth;
-
-#ifdef CONFIG_DEBUG_LOCKDEP
-/*
- * Various lockdep statistics:
- */
-extern atomic_t chain_lookup_hits;
-extern atomic_t chain_lookup_misses;
-extern atomic_t hardirqs_on_events;
-extern atomic_t hardirqs_off_events;
-extern atomic_t redundant_hardirqs_on;
-extern atomic_t redundant_hardirqs_off;
-extern atomic_t softirqs_on_events;
-extern atomic_t softirqs_off_events;
-extern atomic_t redundant_softirqs_on;
-extern atomic_t redundant_softirqs_off;
-extern atomic_t nr_unused_locks;
-extern atomic_t nr_cyclic_checks;
-extern atomic_t nr_cyclic_check_recursions;
-extern atomic_t nr_find_usage_forwards_checks;
-extern atomic_t nr_find_usage_forwards_recursions;
-extern atomic_t nr_find_usage_backwards_checks;
-extern atomic_t nr_find_usage_backwards_recursions;
-# define debug_atomic_inc(ptr)		atomic_inc(ptr)
-# define debug_atomic_dec(ptr)		atomic_dec(ptr)
-# define debug_atomic_read(ptr)		atomic_read(ptr)
-#else
-# define debug_atomic_inc(ptr)		do { } while (0)
-# define debug_atomic_dec(ptr)		do { } while (0)
-# define debug_atomic_read(ptr)		0
-#endif
Index: linux-2.6-lttng.stable/kernel/lockdep_proc.c
===================================================================
--- linux-2.6-lttng.stable.orig/kernel/lockdep_proc.c	2007-10-29 09:51:06.000000000 -0400
+++ /dev/null	1970-01-01 00:00:00.000000000 +0000
@@ -1,683 +0,0 @@
-/*
- * kernel/lockdep_proc.c
- *
- * Runtime locking correctness validator
- *
- * Started by Ingo Molnar:
- *
- *  Copyright (C) 2006,2007 Red Hat, Inc., Ingo Molnar <mingo@xxxxxxxxxx>
- *  Copyright (C) 2007 Red Hat, Inc., Peter Zijlstra <pzijlstr@xxxxxxxxxx>
- *
- * Code for /proc/lockdep and /proc/lockdep_stats:
- *
- */
-#include <linux/module.h>
-#include <linux/proc_fs.h>
-#include <linux/seq_file.h>
-#include <linux/kallsyms.h>
-#include <linux/debug_locks.h>
-#include <linux/vmalloc.h>
-#include <linux/sort.h>
-#include <asm/uaccess.h>
-#include <asm/div64.h>
-
-#include "lockdep_internals.h"
-
-static void *l_next(struct seq_file *m, void *v, loff_t *pos)
-{
-	struct lock_class *class;
-
-	(*pos)++;
-
-	if (v == SEQ_START_TOKEN)
-		class = m->private;
-	else {
-		class = v;
-
-		if (class->lock_entry.next != &all_lock_classes)
-			class = list_entry(class->lock_entry.next,
-					   struct lock_class, lock_entry);
-		else
-			class = NULL;
-	}
-
-	return class;
-}
-
-static void *l_start(struct seq_file *m, loff_t *pos)
-{
-	struct lock_class *class;
-	loff_t i = 0;
-
-	if (*pos == 0)
-		return SEQ_START_TOKEN;
-
-	list_for_each_entry(class, &all_lock_classes, lock_entry) {
-		if (++i == *pos)
-		return class;
-	}
-	return NULL;
-}
-
-static void l_stop(struct seq_file *m, void *v)
-{
-}
-
-static unsigned long count_forward_deps(struct lock_class *class)
-{
-	struct lock_list *entry;
-	unsigned long ret = 1;
-
-	/*
-	 * Recurse this class's dependency list:
-	 */
-	list_for_each_entry(entry, &class->locks_after, entry)
-		ret += count_forward_deps(entry->class);
-
-	return ret;
-}
-
-static unsigned long count_backward_deps(struct lock_class *class)
-{
-	struct lock_list *entry;
-	unsigned long ret = 1;
-
-	/*
-	 * Recurse this class's dependency list:
-	 */
-	list_for_each_entry(entry, &class->locks_before, entry)
-		ret += count_backward_deps(entry->class);
-
-	return ret;
-}
-
-static void print_name(struct seq_file *m, struct lock_class *class)
-{
-	char str[128];
-	const char *name = class->name;
-
-	if (!name) {
-		name = __get_key_name(class->key, str);
-		seq_printf(m, "%s", name);
-	} else{
-		seq_printf(m, "%s", name);
-		if (class->name_version > 1)
-			seq_printf(m, "#%d", class->name_version);
-		if (class->subclass)
-			seq_printf(m, "/%d", class->subclass);
-	}
-}
-
-static int l_show(struct seq_file *m, void *v)
-{
-	unsigned long nr_forward_deps, nr_backward_deps;
-	struct lock_class *class = v;
-	struct lock_list *entry;
-	char c1, c2, c3, c4;
-
-	if (v == SEQ_START_TOKEN) {
-		seq_printf(m, "all lock classes:\n");
-		return 0;
-	}
-
-	seq_printf(m, "%p", class->key);
-#ifdef CONFIG_DEBUG_LOCKDEP
-	seq_printf(m, " OPS:%8ld", class->ops);
-#endif
-	nr_forward_deps = count_forward_deps(class);
-	seq_printf(m, " FD:%5ld", nr_forward_deps);
-
-	nr_backward_deps = count_backward_deps(class);
-	seq_printf(m, " BD:%5ld", nr_backward_deps);
-
-	get_usage_chars(class, &c1, &c2, &c3, &c4);
-	seq_printf(m, " %c%c%c%c", c1, c2, c3, c4);
-
-	seq_printf(m, ": ");
-	print_name(m, class);
-	seq_puts(m, "\n");
-
-	list_for_each_entry(entry, &class->locks_after, entry) {
-		if (entry->distance == 1) {
-			seq_printf(m, " -> [%p] ", entry->class);
-			print_name(m, entry->class);
-			seq_puts(m, "\n");
-		}
-	}
-	seq_puts(m, "\n");
-
-	return 0;
-}
-
-static const struct seq_operations lockdep_ops = {
-	.start	= l_start,
-	.next	= l_next,
-	.stop	= l_stop,
-	.show	= l_show,
-};
-
-static int lockdep_open(struct inode *inode, struct file *file)
-{
-	int res = seq_open(file, &lockdep_ops);
-	if (!res) {
-		struct seq_file *m = file->private_data;
-
-		if (!list_empty(&all_lock_classes))
-			m->private = list_entry(all_lock_classes.next,
-					struct lock_class, lock_entry);
-		else
-			m->private = NULL;
-	}
-	return res;
-}
-
-static const struct file_operations proc_lockdep_operations = {
-	.open		= lockdep_open,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= seq_release,
-};
-
-static void lockdep_stats_debug_show(struct seq_file *m)
-{
-#ifdef CONFIG_DEBUG_LOCKDEP
-	unsigned int hi1 = debug_atomic_read(&hardirqs_on_events),
-		     hi2 = debug_atomic_read(&hardirqs_off_events),
-		     hr1 = debug_atomic_read(&redundant_hardirqs_on),
-		     hr2 = debug_atomic_read(&redundant_hardirqs_off),
-		     si1 = debug_atomic_read(&softirqs_on_events),
-		     si2 = debug_atomic_read(&softirqs_off_events),
-		     sr1 = debug_atomic_read(&redundant_softirqs_on),
-		     sr2 = debug_atomic_read(&redundant_softirqs_off);
-
-	seq_printf(m, " chain lookup misses:           %11u\n",
-		debug_atomic_read(&chain_lookup_misses));
-	seq_printf(m, " chain lookup hits:             %11u\n",
-		debug_atomic_read(&chain_lookup_hits));
-	seq_printf(m, " cyclic checks:                 %11u\n",
-		debug_atomic_read(&nr_cyclic_checks));
-	seq_printf(m, " cyclic-check recursions:       %11u\n",
-		debug_atomic_read(&nr_cyclic_check_recursions));
-	seq_printf(m, " find-mask forwards checks:     %11u\n",
-		debug_atomic_read(&nr_find_usage_forwards_checks));
-	seq_printf(m, " find-mask forwards recursions: %11u\n",
-		debug_atomic_read(&nr_find_usage_forwards_recursions));
-	seq_printf(m, " find-mask backwards checks:    %11u\n",
-		debug_atomic_read(&nr_find_usage_backwards_checks));
-	seq_printf(m, " find-mask backwards recursions:%11u\n",
-		debug_atomic_read(&nr_find_usage_backwards_recursions));
-
-	seq_printf(m, " hardirq on events:             %11u\n", hi1);
-	seq_printf(m, " hardirq off events:            %11u\n", hi2);
-	seq_printf(m, " redundant hardirq ons:         %11u\n", hr1);
-	seq_printf(m, " redundant hardirq offs:        %11u\n", hr2);
-	seq_printf(m, " softirq on events:             %11u\n", si1);
-	seq_printf(m, " softirq off events:            %11u\n", si2);
-	seq_printf(m, " redundant softirq ons:         %11u\n", sr1);
-	seq_printf(m, " redundant softirq offs:        %11u\n", sr2);
-#endif
-}
-
-static int lockdep_stats_show(struct seq_file *m, void *v)
-{
-	struct lock_class *class;
-	unsigned long nr_unused = 0, nr_uncategorized = 0,
-		      nr_irq_safe = 0, nr_irq_unsafe = 0,
-		      nr_softirq_safe = 0, nr_softirq_unsafe = 0,
-		      nr_hardirq_safe = 0, nr_hardirq_unsafe = 0,
-		      nr_irq_read_safe = 0, nr_irq_read_unsafe = 0,
-		      nr_softirq_read_safe = 0, nr_softirq_read_unsafe = 0,
-		      nr_hardirq_read_safe = 0, nr_hardirq_read_unsafe = 0,
-		      sum_forward_deps = 0, factor = 0;
-
-	list_for_each_entry(class, &all_lock_classes, lock_entry) {
-
-		if (class->usage_mask == 0)
-			nr_unused++;
-		if (class->usage_mask == LOCKF_USED)
-			nr_uncategorized++;
-		if (class->usage_mask & LOCKF_USED_IN_IRQ)
-			nr_irq_safe++;
-		if (class->usage_mask & LOCKF_ENABLED_IRQS)
-			nr_irq_unsafe++;
-		if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ)
-			nr_softirq_safe++;
-		if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS)
-			nr_softirq_unsafe++;
-		if (class->usage_mask & LOCKF_USED_IN_HARDIRQ)
-			nr_hardirq_safe++;
-		if (class->usage_mask & LOCKF_ENABLED_HARDIRQS)
-			nr_hardirq_unsafe++;
-		if (class->usage_mask & LOCKF_USED_IN_IRQ_READ)
-			nr_irq_read_safe++;
-		if (class->usage_mask & LOCKF_ENABLED_IRQS_READ)
-			nr_irq_read_unsafe++;
-		if (class->usage_mask & LOCKF_USED_IN_SOFTIRQ_READ)
-			nr_softirq_read_safe++;
-		if (class->usage_mask & LOCKF_ENABLED_SOFTIRQS_READ)
-			nr_softirq_read_unsafe++;
-		if (class->usage_mask & LOCKF_USED_IN_HARDIRQ_READ)
-			nr_hardirq_read_safe++;
-		if (class->usage_mask & LOCKF_ENABLED_HARDIRQS_READ)
-			nr_hardirq_read_unsafe++;
-
-		sum_forward_deps += count_forward_deps(class);
-	}
-#ifdef CONFIG_DEBUG_LOCKDEP
-	DEBUG_LOCKS_WARN_ON(debug_atomic_read(&nr_unused_locks) != nr_unused);
-#endif
-	seq_printf(m, " lock-classes:                  %11lu [max: %lu]\n",
-			nr_lock_classes, MAX_LOCKDEP_KEYS);
-	seq_printf(m, " direct dependencies:           %11lu [max: %lu]\n",
-			nr_list_entries, MAX_LOCKDEP_ENTRIES);
-	seq_printf(m, " indirect dependencies:         %11lu\n",
-			sum_forward_deps);
-
-	/*
-	 * Total number of dependencies:
-	 *
-	 * All irq-safe locks may nest inside irq-unsafe locks,
-	 * plus all the other known dependencies:
-	 */
-	seq_printf(m, " all direct dependencies:       %11lu\n",
-			nr_irq_unsafe * nr_irq_safe +
-			nr_hardirq_unsafe * nr_hardirq_safe +
-			nr_list_entries);
-
-	/*
-	 * Estimated factor between direct and indirect
-	 * dependencies:
-	 */
-	if (nr_list_entries)
-		factor = sum_forward_deps / nr_list_entries;
-
-#ifdef CONFIG_PROVE_LOCKING
-	seq_printf(m, " dependency chains:             %11lu [max: %lu]\n",
-			nr_lock_chains, MAX_LOCKDEP_CHAINS);
-#endif
-
-#ifdef CONFIG_TRACE_IRQFLAGS
-	seq_printf(m, " in-hardirq chains:             %11u\n",
-			nr_hardirq_chains);
-	seq_printf(m, " in-softirq chains:             %11u\n",
-			nr_softirq_chains);
-#endif
-	seq_printf(m, " in-process chains:             %11u\n",
-			nr_process_chains);
-	seq_printf(m, " stack-trace entries:           %11lu [max: %lu]\n",
-			nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES);
-	seq_printf(m, " combined max dependencies:     %11u\n",
-			(nr_hardirq_chains + 1) *
-			(nr_softirq_chains + 1) *
-			(nr_process_chains + 1)
-	);
-	seq_printf(m, " hardirq-safe locks:            %11lu\n",
-			nr_hardirq_safe);
-	seq_printf(m, " hardirq-unsafe locks:          %11lu\n",
-			nr_hardirq_unsafe);
-	seq_printf(m, " softirq-safe locks:            %11lu\n",
-			nr_softirq_safe);
-	seq_printf(m, " softirq-unsafe locks:          %11lu\n",
-			nr_softirq_unsafe);
-	seq_printf(m, " irq-safe locks:                %11lu\n",
-			nr_irq_safe);
-	seq_printf(m, " irq-unsafe locks:              %11lu\n",
-			nr_irq_unsafe);
-
-	seq_printf(m, " hardirq-read-safe locks:       %11lu\n",
-			nr_hardirq_read_safe);
-	seq_printf(m, " hardirq-read-unsafe locks:     %11lu\n",
-			nr_hardirq_read_unsafe);
-	seq_printf(m, " softirq-read-safe locks:       %11lu\n",
-			nr_softirq_read_safe);
-	seq_printf(m, " softirq-read-unsafe locks:     %11lu\n",
-			nr_softirq_read_unsafe);
-	seq_printf(m, " irq-read-safe locks:           %11lu\n",
-			nr_irq_read_safe);
-	seq_printf(m, " irq-read-unsafe locks:         %11lu\n",
-			nr_irq_read_unsafe);
-
-	seq_printf(m, " uncategorized locks:           %11lu\n",
-			nr_uncategorized);
-	seq_printf(m, " unused locks:                  %11lu\n",
-			nr_unused);
-	seq_printf(m, " max locking depth:             %11u\n",
-			max_lockdep_depth);
-	seq_printf(m, " max recursion depth:           %11u\n",
-			max_recursion_depth);
-	lockdep_stats_debug_show(m);
-	seq_printf(m, " debug_locks:                   %11u\n",
-			debug_locks);
-
-	return 0;
-}
-
-static int lockdep_stats_open(struct inode *inode, struct file *file)
-{
-	return single_open(file, lockdep_stats_show, NULL);
-}
-
-static const struct file_operations proc_lockdep_stats_operations = {
-	.open		= lockdep_stats_open,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= single_release,
-};
-
-#ifdef CONFIG_LOCK_STAT
-
-struct lock_stat_data {
-	struct lock_class *class;
-	struct lock_class_stats stats;
-};
-
-struct lock_stat_seq {
-	struct lock_stat_data *iter;
-	struct lock_stat_data *iter_end;
-	struct lock_stat_data stats[MAX_LOCKDEP_KEYS];
-};
-
-/*
- * sort on absolute number of contentions
- */
-static int lock_stat_cmp(const void *l, const void *r)
-{
-	const struct lock_stat_data *dl = l, *dr = r;
-	unsigned long nl, nr;
-
-	nl = dl->stats.read_waittime.nr + dl->stats.write_waittime.nr;
-	nr = dr->stats.read_waittime.nr + dr->stats.write_waittime.nr;
-
-	return nr - nl;
-}
-
-static void seq_line(struct seq_file *m, char c, int offset, int length)
-{
-	int i;
-
-	for (i = 0; i < offset; i++)
-		seq_puts(m, " ");
-	for (i = 0; i < length; i++)
-		seq_printf(m, "%c", c);
-	seq_puts(m, "\n");
-}
-
-static void snprint_time(char *buf, size_t bufsiz, s64 nr)
-{
-	unsigned long rem;
-
-	rem = do_div(nr, 1000); /* XXX: do_div_signed */
-	snprintf(buf, bufsiz, "%lld.%02d", (long long)nr, ((int)rem+5)/10);
-}
-
-static void seq_time(struct seq_file *m, s64 time)
-{
-	char num[15];
-
-	snprint_time(num, sizeof(num), time);
-	seq_printf(m, " %14s", num);
-}
-
-static void seq_lock_time(struct seq_file *m, struct lock_time *lt)
-{
-	seq_printf(m, "%14lu", lt->nr);
-	seq_time(m, lt->min);
-	seq_time(m, lt->max);
-	seq_time(m, lt->total);
-}
-
-static void seq_stats(struct seq_file *m, struct lock_stat_data *data)
-{
-	char name[39];
-	struct lock_class *class;
-	struct lock_class_stats *stats;
-	int i, namelen;
-
-	class = data->class;
-	stats = &data->stats;
-
-	namelen = 38;
-	if (class->name_version > 1)
-		namelen -= 2; /* XXX truncates versions > 9 */
-	if (class->subclass)
-		namelen -= 2;
-
-	if (!class->name) {
-		char str[KSYM_NAME_LEN];
-		const char *key_name;
-
-		key_name = __get_key_name(class->key, str);
-		snprintf(name, namelen, "%s", key_name);
-	} else {
-		snprintf(name, namelen, "%s", class->name);
-	}
-	namelen = strlen(name);
-	if (class->name_version > 1) {
-		snprintf(name+namelen, 3, "#%d", class->name_version);
-		namelen += 2;
-	}
-	if (class->subclass) {
-		snprintf(name+namelen, 3, "/%d", class->subclass);
-		namelen += 2;
-	}
-
-	if (stats->write_holdtime.nr) {
-		if (stats->read_holdtime.nr)
-			seq_printf(m, "%38s-W:", name);
-		else
-			seq_printf(m, "%40s:", name);
-
-		seq_printf(m, "%14lu ", stats->bounces[bounce_contended_write]);
-		seq_lock_time(m, &stats->write_waittime);
-		seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_write]);
-		seq_lock_time(m, &stats->write_holdtime);
-		seq_puts(m, "\n");
-	}
-
-	if (stats->read_holdtime.nr) {
-		seq_printf(m, "%38s-R:", name);
-		seq_printf(m, "%14lu ", stats->bounces[bounce_contended_read]);
-		seq_lock_time(m, &stats->read_waittime);
-		seq_printf(m, " %14lu ", stats->bounces[bounce_acquired_read]);
-		seq_lock_time(m, &stats->read_holdtime);
-		seq_puts(m, "\n");
-	}
-
-	if (stats->read_waittime.nr + stats->write_waittime.nr == 0)
-		return;
-
-	if (stats->read_holdtime.nr)
-		namelen += 2;
-
-	for (i = 0; i < ARRAY_SIZE(class->contention_point); i++) {
-		char sym[KSYM_SYMBOL_LEN];
-		char ip[32];
-
-		if (class->contention_point[i] == 0)
-			break;
-
-		if (!i)
-			seq_line(m, '-', 40-namelen, namelen);
-
-		sprint_symbol(sym, class->contention_point[i]);
-		snprintf(ip, sizeof(ip), "[<%p>]",
-				(void *)class->contention_point[i]);
-		seq_printf(m, "%40s %14lu %29s %s\n", name,
-				stats->contention_point[i],
-				ip, sym);
-	}
-	if (i) {
-		seq_puts(m, "\n");
-		seq_line(m, '.', 0, 40 + 1 + 10 * (14 + 1));
-		seq_puts(m, "\n");
-	}
-}
-
-static void seq_header(struct seq_file *m)
-{
-	seq_printf(m, "lock_stat version 0.2\n");
-	seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
-	seq_printf(m, "%40s %14s %14s %14s %14s %14s %14s %14s %14s "
-			"%14s %14s\n",
-			"class name",
-			"con-bounces",
-			"contentions",
-			"waittime-min",
-			"waittime-max",
-			"waittime-total",
-			"acq-bounces",
-			"acquisitions",
-			"holdtime-min",
-			"holdtime-max",
-			"holdtime-total");
-	seq_line(m, '-', 0, 40 + 1 + 10 * (14 + 1));
-	seq_printf(m, "\n");
-}
-
-static void *ls_start(struct seq_file *m, loff_t *pos)
-{
-	struct lock_stat_seq *data = m->private;
-
-	if (*pos == 0)
-		return SEQ_START_TOKEN;
-
-	data->iter = data->stats + *pos;
-	if (data->iter >= data->iter_end)
-		data->iter = NULL;
-
-	return data->iter;
-}
-
-static void *ls_next(struct seq_file *m, void *v, loff_t *pos)
-{
-	struct lock_stat_seq *data = m->private;
-
-	(*pos)++;
-
-	if (v == SEQ_START_TOKEN)
-		data->iter = data->stats;
-	else {
-		data->iter = v;
-		data->iter++;
-	}
-
-	if (data->iter == data->iter_end)
-		data->iter = NULL;
-
-	return data->iter;
-}
-
-static void ls_stop(struct seq_file *m, void *v)
-{
-}
-
-static int ls_show(struct seq_file *m, void *v)
-{
-	if (v == SEQ_START_TOKEN)
-		seq_header(m);
-	else
-		seq_stats(m, v);
-
-	return 0;
-}
-
-static struct seq_operations lockstat_ops = {
-	.start	= ls_start,
-	.next	= ls_next,
-	.stop	= ls_stop,
-	.show	= ls_show,
-};
-
-static int lock_stat_open(struct inode *inode, struct file *file)
-{
-	int res;
-	struct lock_class *class;
-	struct lock_stat_seq *data = vmalloc(sizeof(struct lock_stat_seq));
-
-	if (!data)
-		return -ENOMEM;
-
-	res = seq_open(file, &lockstat_ops);
-	if (!res) {
-		struct lock_stat_data *iter = data->stats;
-		struct seq_file *m = file->private_data;
-
-		data->iter = iter;
-		list_for_each_entry(class, &all_lock_classes, lock_entry) {
-			iter->class = class;
-			iter->stats = lock_stats(class);
-			iter++;
-		}
-		data->iter_end = iter;
-
-		sort(data->stats, data->iter_end - data->iter,
-				sizeof(struct lock_stat_data),
-				lock_stat_cmp, NULL);
-
-		m->private = data;
-	} else
-		vfree(data);
-
-	return res;
-}
-
-static ssize_t lock_stat_write(struct file *file, const char __user *buf,
-			       size_t count, loff_t *ppos)
-{
-	struct lock_class *class;
-	char c;
-
-	if (count) {
-		if (get_user(c, buf))
-			return -EFAULT;
-
-		if (c != '0')
-			return count;
-
-		list_for_each_entry(class, &all_lock_classes, lock_entry)
-			clear_lock_stats(class);
-	}
-	return count;
-}
-
-static int lock_stat_release(struct inode *inode, struct file *file)
-{
-	struct seq_file *seq = file->private_data;
-
-	vfree(seq->private);
-	seq->private = NULL;
-	return seq_release(inode, file);
-}
-
-static const struct file_operations proc_lock_stat_operations = {
-	.open		= lock_stat_open,
-	.write		= lock_stat_write,
-	.read		= seq_read,
-	.llseek		= seq_lseek,
-	.release	= lock_stat_release,
-};
-#endif /* CONFIG_LOCK_STAT */
-
-static int __init lockdep_proc_init(void)
-{
-	struct proc_dir_entry *entry;
-
-	entry = create_proc_entry("lockdep", S_IRUSR, NULL);
-	if (entry)
-		entry->proc_fops = &proc_lockdep_operations;
-
-	entry = create_proc_entry("lockdep_stats", S_IRUSR, NULL);
-	if (entry)
-		entry->proc_fops = &proc_lockdep_stats_operations;
-
-#ifdef CONFIG_LOCK_STAT
-	entry = create_proc_entry("lock_stat", S_IRUSR, NULL);
-	if (entry)
-		entry->proc_fops = &proc_lock_stat_operations;
-#endif
-
-	return 0;
-}
-
-__initcall(lockdep_proc_init);
-

-- 
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
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