[GIT PULL] perf fixes
From: Ingo Molnar
Date: Fri Nov 26 2010 - 08:21:15 EST
Linus,
Please pull the latest perf-fixes-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git perf-fixes-for-linus
Thanks,
Ingo
------------------>
Arnaldo Carvalho de Melo (1):
perf record: Handle restrictive permissions in /proc/{kallsyms,modules}
Frederic Weisbecker (1):
x86: Ignore trap bits on single step exceptions
Jason Wessel (1):
perf,hw_breakpoint: Initialize hardware api earlier
Masami Hiramatsu (1):
x86/kprobes: Prevent kprobes to probe on save_args()
Peter Zijlstra (1):
perf: Fix owner-list vs exit
Rabin Vincent (1):
perf symbols: Remove incorrect open-coded container_of()
Rakib Mullick (1):
x86, hw_nmi: Move backtrace_mask declaration under ARCH_HAS_NMI_WATCHDOG
Sergio Aguirre (1):
irq_work: Drop cmpxchg() result
Steven Rostedt (3):
tracing: Fix module use of trace_bprintk()
tracing: Force arch_local_irq_* notrace for paravirt
tracing: Fix recursive user stack trace
arch/x86/include/asm/paravirt.h | 10 +++---
arch/x86/kernel/apic/hw_nmi.c | 7 ++--
arch/x86/kernel/entry_64.S | 2 +
arch/x86/kernel/hw_breakpoint.c | 4 ++
include/linux/hw_breakpoint.h | 4 ++
kernel/hw_breakpoint.c | 3 +-
kernel/irq_work.c | 4 ++-
kernel/module.c | 12 +++++++
kernel/perf_event.c | 69 ++++++++++++++++++++++++++++++++-------
kernel/trace/trace.c | 19 +++++++++++
tools/perf/builtin-record.c | 17 +++++----
tools/perf/util/symbol.c | 4 ++-
12 files changed, 123 insertions(+), 32 deletions(-)
diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 18e3b8a..ef99758 100644
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -824,27 +824,27 @@ static __always_inline void arch_spin_unlock(struct arch_spinlock *lock)
#define __PV_IS_CALLEE_SAVE(func) \
((struct paravirt_callee_save) { func })
-static inline unsigned long arch_local_save_flags(void)
+static inline notrace unsigned long arch_local_save_flags(void)
{
return PVOP_CALLEE0(unsigned long, pv_irq_ops.save_fl);
}
-static inline void arch_local_irq_restore(unsigned long f)
+static inline notrace void arch_local_irq_restore(unsigned long f)
{
PVOP_VCALLEE1(pv_irq_ops.restore_fl, f);
}
-static inline void arch_local_irq_disable(void)
+static inline notrace void arch_local_irq_disable(void)
{
PVOP_VCALLEE0(pv_irq_ops.irq_disable);
}
-static inline void arch_local_irq_enable(void)
+static inline notrace void arch_local_irq_enable(void)
{
PVOP_VCALLEE0(pv_irq_ops.irq_enable);
}
-static inline unsigned long arch_local_irq_save(void)
+static inline notrace unsigned long arch_local_irq_save(void)
{
unsigned long f;
diff --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c
index cefd694..62f6e1e 100644
--- a/arch/x86/kernel/apic/hw_nmi.c
+++ b/arch/x86/kernel/apic/hw_nmi.c
@@ -17,15 +17,16 @@
#include <linux/nmi.h>
#include <linux/module.h>
-/* For reliability, we're prepared to waste bits here. */
-static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
-
u64 hw_nmi_get_sample_period(void)
{
return (u64)(cpu_khz) * 1000 * 60;
}
#ifdef ARCH_HAS_NMI_WATCHDOG
+
+/* For reliability, we're prepared to waste bits here. */
+static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
+
void arch_trigger_all_cpu_backtrace(void)
{
int i;
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index fe2690d..e3ba417 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -295,6 +295,7 @@ ENDPROC(native_usergs_sysret64)
.endm
/* save partial stack frame */
+ .pushsection .kprobes.text, "ax"
ENTRY(save_args)
XCPT_FRAME
cld
@@ -334,6 +335,7 @@ ENTRY(save_args)
ret
CFI_ENDPROC
END(save_args)
+ .popsection
ENTRY(save_rest)
PARTIAL_FRAME 1 REST_SKIP+8
diff --git a/arch/x86/kernel/hw_breakpoint.c b/arch/x86/kernel/hw_breakpoint.c
index ff15c9d..42c5942 100644
--- a/arch/x86/kernel/hw_breakpoint.c
+++ b/arch/x86/kernel/hw_breakpoint.c
@@ -433,6 +433,10 @@ static int __kprobes hw_breakpoint_handler(struct die_args *args)
dr6_p = (unsigned long *)ERR_PTR(args->err);
dr6 = *dr6_p;
+ /* If it's a single step, TRAP bits are random */
+ if (dr6 & DR_STEP)
+ return NOTIFY_DONE;
+
/* Do an early return if no trap bits are set in DR6 */
if ((dr6 & DR_TRAP_BITS) == 0)
return NOTIFY_DONE;
diff --git a/include/linux/hw_breakpoint.h b/include/linux/hw_breakpoint.h
index a2d6ea4..d1e55fe 100644
--- a/include/linux/hw_breakpoint.h
+++ b/include/linux/hw_breakpoint.h
@@ -33,6 +33,8 @@ enum bp_type_idx {
#ifdef CONFIG_HAVE_HW_BREAKPOINT
+extern int __init init_hw_breakpoint(void);
+
static inline void hw_breakpoint_init(struct perf_event_attr *attr)
{
memset(attr, 0, sizeof(*attr));
@@ -108,6 +110,8 @@ static inline struct arch_hw_breakpoint *counter_arch_bp(struct perf_event *bp)
#else /* !CONFIG_HAVE_HW_BREAKPOINT */
+static inline int __init init_hw_breakpoint(void) { return 0; }
+
static inline struct perf_event *
register_user_hw_breakpoint(struct perf_event_attr *attr,
perf_overflow_handler_t triggered,
diff --git a/kernel/hw_breakpoint.c b/kernel/hw_breakpoint.c
index 2c9120f..e532582 100644
--- a/kernel/hw_breakpoint.c
+++ b/kernel/hw_breakpoint.c
@@ -620,7 +620,7 @@ static struct pmu perf_breakpoint = {
.read = hw_breakpoint_pmu_read,
};
-static int __init init_hw_breakpoint(void)
+int __init init_hw_breakpoint(void)
{
unsigned int **task_bp_pinned;
int cpu, err_cpu;
@@ -655,6 +655,5 @@ static int __init init_hw_breakpoint(void)
return -ENOMEM;
}
-core_initcall(init_hw_breakpoint);
diff --git a/kernel/irq_work.c b/kernel/irq_work.c
index f16763f..90f8819 100644
--- a/kernel/irq_work.c
+++ b/kernel/irq_work.c
@@ -145,7 +145,9 @@ void irq_work_run(void)
* Clear the BUSY bit and return to the free state if
* no-one else claimed it meanwhile.
*/
- cmpxchg(&entry->next, next_flags(NULL, IRQ_WORK_BUSY), NULL);
+ (void)cmpxchg(&entry->next,
+ next_flags(NULL, IRQ_WORK_BUSY),
+ NULL);
}
}
EXPORT_SYMBOL_GPL(irq_work_run);
diff --git a/kernel/module.c b/kernel/module.c
index 437a74a..d190664 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -2326,6 +2326,18 @@ static void find_module_sections(struct module *mod, struct load_info *info)
kmemleak_scan_area(mod->trace_events, sizeof(*mod->trace_events) *
mod->num_trace_events, GFP_KERNEL);
#endif
+#ifdef CONFIG_TRACING
+ mod->trace_bprintk_fmt_start = section_objs(info, "__trace_printk_fmt",
+ sizeof(*mod->trace_bprintk_fmt_start),
+ &mod->num_trace_bprintk_fmt);
+ /*
+ * This section contains pointers to allocated objects in the trace
+ * code and not scanning it leads to false positives.
+ */
+ kmemleak_scan_area(mod->trace_bprintk_fmt_start,
+ sizeof(*mod->trace_bprintk_fmt_start) *
+ mod->num_trace_bprintk_fmt, GFP_KERNEL);
+#endif
#ifdef CONFIG_FTRACE_MCOUNT_RECORD
/* sechdrs[0].sh_size is always zero */
mod->ftrace_callsites = section_objs(info, "__mcount_loc",
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index cb6c0d2..671f6c8 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -31,6 +31,7 @@
#include <linux/kernel_stat.h>
#include <linux/perf_event.h>
#include <linux/ftrace_event.h>
+#include <linux/hw_breakpoint.h>
#include <asm/irq_regs.h>
@@ -2234,11 +2235,6 @@ int perf_event_release_kernel(struct perf_event *event)
raw_spin_unlock_irq(&ctx->lock);
mutex_unlock(&ctx->mutex);
- mutex_lock(&event->owner->perf_event_mutex);
- list_del_init(&event->owner_entry);
- mutex_unlock(&event->owner->perf_event_mutex);
- put_task_struct(event->owner);
-
free_event(event);
return 0;
@@ -2251,9 +2247,43 @@ EXPORT_SYMBOL_GPL(perf_event_release_kernel);
static int perf_release(struct inode *inode, struct file *file)
{
struct perf_event *event = file->private_data;
+ struct task_struct *owner;
file->private_data = NULL;
+ rcu_read_lock();
+ owner = ACCESS_ONCE(event->owner);
+ /*
+ * Matches the smp_wmb() in perf_event_exit_task(). If we observe
+ * !owner it means the list deletion is complete and we can indeed
+ * free this event, otherwise we need to serialize on
+ * owner->perf_event_mutex.
+ */
+ smp_read_barrier_depends();
+ if (owner) {
+ /*
+ * Since delayed_put_task_struct() also drops the last
+ * task reference we can safely take a new reference
+ * while holding the rcu_read_lock().
+ */
+ get_task_struct(owner);
+ }
+ rcu_read_unlock();
+
+ if (owner) {
+ mutex_lock(&owner->perf_event_mutex);
+ /*
+ * We have to re-check the event->owner field, if it is cleared
+ * we raced with perf_event_exit_task(), acquiring the mutex
+ * ensured they're done, and we can proceed with freeing the
+ * event.
+ */
+ if (event->owner)
+ list_del_init(&event->owner_entry);
+ mutex_unlock(&owner->perf_event_mutex);
+ put_task_struct(owner);
+ }
+
return perf_event_release_kernel(event);
}
@@ -5677,7 +5707,7 @@ SYSCALL_DEFINE5(perf_event_open,
mutex_unlock(&ctx->mutex);
event->owner = current;
- get_task_struct(current);
+
mutex_lock(¤t->perf_event_mutex);
list_add_tail(&event->owner_entry, ¤t->perf_event_list);
mutex_unlock(¤t->perf_event_mutex);
@@ -5745,12 +5775,6 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
++ctx->generation;
mutex_unlock(&ctx->mutex);
- event->owner = current;
- get_task_struct(current);
- mutex_lock(¤t->perf_event_mutex);
- list_add_tail(&event->owner_entry, ¤t->perf_event_list);
- mutex_unlock(¤t->perf_event_mutex);
-
return event;
err_free:
@@ -5901,8 +5925,24 @@ again:
*/
void perf_event_exit_task(struct task_struct *child)
{
+ struct perf_event *event, *tmp;
int ctxn;
+ mutex_lock(&child->perf_event_mutex);
+ list_for_each_entry_safe(event, tmp, &child->perf_event_list,
+ owner_entry) {
+ list_del_init(&event->owner_entry);
+
+ /*
+ * Ensure the list deletion is visible before we clear
+ * the owner, closes a race against perf_release() where
+ * we need to serialize on the owner->perf_event_mutex.
+ */
+ smp_wmb();
+ event->owner = NULL;
+ }
+ mutex_unlock(&child->perf_event_mutex);
+
for_each_task_context_nr(ctxn)
perf_event_exit_task_context(child, ctxn);
}
@@ -6321,6 +6361,8 @@ perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
void __init perf_event_init(void)
{
+ int ret;
+
perf_event_init_all_cpus();
init_srcu_struct(&pmus_srcu);
perf_pmu_register(&perf_swevent);
@@ -6328,4 +6370,7 @@ void __init perf_event_init(void)
perf_pmu_register(&perf_task_clock);
perf_tp_register();
perf_cpu_notifier(perf_cpu_notify);
+
+ ret = init_hw_breakpoint();
+ WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
}
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 82d9b81..ee6a733 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -1284,6 +1284,8 @@ void trace_dump_stack(void)
__ftrace_trace_stack(global_trace.buffer, flags, 3, preempt_count());
}
+static DEFINE_PER_CPU(int, user_stack_count);
+
void
ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
{
@@ -1302,6 +1304,18 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
if (unlikely(in_nmi()))
return;
+ /*
+ * prevent recursion, since the user stack tracing may
+ * trigger other kernel events.
+ */
+ preempt_disable();
+ if (__this_cpu_read(user_stack_count))
+ goto out;
+
+ __this_cpu_inc(user_stack_count);
+
+
+
event = trace_buffer_lock_reserve(buffer, TRACE_USER_STACK,
sizeof(*entry), flags, pc);
if (!event)
@@ -1319,6 +1333,11 @@ ftrace_trace_userstack(struct ring_buffer *buffer, unsigned long flags, int pc)
save_stack_trace_user(&trace);
if (!filter_check_discard(call, entry, buffer, event))
ring_buffer_unlock_commit(buffer, event);
+
+ __this_cpu_dec(user_stack_count);
+
+ out:
+ preempt_enable();
}
#ifdef UNUSED
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 93bd2ff..e2c2de2 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -697,17 +697,18 @@ static int __cmd_record(int argc, const char **argv)
if (err < 0)
err = event__synthesize_kernel_mmap(process_synthesized_event,
session, machine, "_stext");
- if (err < 0) {
- pr_err("Couldn't record kernel reference relocation symbol.\n");
- return err;
- }
+ if (err < 0)
+ pr_err("Couldn't record kernel reference relocation symbol\n"
+ "Symbol resolution may be skewed if relocation was used (e.g. kexec).\n"
+ "Check /proc/kallsyms permission or run as root.\n");
err = event__synthesize_modules(process_synthesized_event,
session, machine);
- if (err < 0) {
- pr_err("Couldn't record kernel reference relocation symbol.\n");
- return err;
- }
+ if (err < 0)
+ pr_err("Couldn't record kernel module information.\n"
+ "Symbol resolution may be skewed if relocation was used (e.g. kexec).\n"
+ "Check /proc/modules permission or run as root.\n");
+
if (perf_guest)
perf_session__process_machines(session, event__synthesize_guest_os);
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index b39f499..0500895 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -295,7 +295,9 @@ static void symbols__insert_by_name(struct rb_root *self, struct symbol *sym)
{
struct rb_node **p = &self->rb_node;
struct rb_node *parent = NULL;
- struct symbol_name_rb_node *symn = ((void *)sym) - sizeof(*parent), *s;
+ struct symbol_name_rb_node *symn, *s;
+
+ symn = container_of(sym, struct symbol_name_rb_node, sym);
while (*p != NULL) {
parent = *p;
--
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