[GIT PULL] tracing: Cleanups for v6.10
From: Steven Rostedt
Date: Thu May 16 2024 - 11:54:58 EST
Linus,
tracing cleanups for v6.10:
- Removed unused ftrace_direct_funcs variables
- Fix a possible NULL pointer dereference race in eventfs
- Update do_div() usage in trace event benchmark test
- Speedup direct function registration with asynchronous RCU callback.
The synchronization was done in the registration code and this
caused delays when registering direct callbacks. Move the freeing
to a call_rcu() that will prevent delaying of the registering.
- Replace simple_strtoul() usage with kstrtoul()
Please pull the latest trace-v6.10 tree, which can be found at:
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git
trace-v6.10
Tag SHA1: 7cb6620f9a48fbdda06bc070c3e6270a39edc76a
Head SHA1: d4e9a968738bf66d3bb852dd5588d4c7afd6d7f4
Dr. David Alan Gilbert (2):
ftrace: Remove unused list 'ftrace_direct_funcs'
ftrace: Remove unused global 'ftrace_direct_func_count'
Hao Ge (1):
eventfs: Fix a possible null pointer dereference in eventfs_find_events()
Paul E. McKenney (1):
ftrace: Use asynchronous grace period for register_ftrace_direct()
Thorsten Blum (1):
tracing: Improve benchmark test performance by using do_div()
Yuran Pereira (1):
ftrace: Replaces simple_strtoul in ftrace
Zheng Yejian (1):
ftrace: Fix possible use-after-free issue in ftrace_location()
----
fs/tracefs/event_inode.c | 7 ++---
include/linux/ftrace.h | 3 --
kernel/trace/fgraph.c | 11 -------
kernel/trace/ftrace.c | 68 ++++++++++++++++++++++--------------------
kernel/trace/trace_benchmark.c | 2 +-
5 files changed, 39 insertions(+), 52 deletions(-)
---------------------------
diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index a878cea70f4c..0256afdd4acf 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -345,10 +345,9 @@ static struct eventfs_inode *eventfs_find_events(struct dentry *dentry)
* If the ei is being freed, the ownership of the children
* doesn't matter.
*/
- if (ei->is_freed) {
- ei = NULL;
- break;
- }
+ if (ei->is_freed)
+ return NULL;
+
// Walk upwards until you find the events inode
} while (!ei->is_events);
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 54d53f345d14..e3a83ebd1b33 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -83,7 +83,6 @@ static inline void early_trace_init(void) { }
struct module;
struct ftrace_hash;
-struct ftrace_direct_func;
#if defined(CONFIG_FUNCTION_TRACER) && defined(CONFIG_MODULES) && \
defined(CONFIG_DYNAMIC_FTRACE)
@@ -414,7 +413,6 @@ struct ftrace_func_entry {
};
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
-extern int ftrace_direct_func_count;
unsigned long ftrace_find_rec_direct(unsigned long ip);
int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr);
int unregister_ftrace_direct(struct ftrace_ops *ops, unsigned long addr,
@@ -426,7 +424,6 @@ void ftrace_stub_direct_tramp(void);
#else
struct ftrace_ops;
-# define ftrace_direct_func_count 0
static inline unsigned long ftrace_find_rec_direct(unsigned long ip)
{
return 0;
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index c83c005e654e..a130b2d898f7 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -125,17 +125,6 @@ int function_graph_enter(unsigned long ret, unsigned long func,
{
struct ftrace_graph_ent trace;
-#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS
- /*
- * Skip graph tracing if the return location is served by direct trampoline,
- * since call sequence and return addresses are unpredictable anyway.
- * Ex: BPF trampoline may call original function and may skip frame
- * depending on type of BPF programs attached.
- */
- if (ftrace_direct_func_count &&
- ftrace_find_rec_direct(ret - MCOUNT_INSN_SIZE))
- return -EBUSY;
-#endif
trace.func = func;
trace.depth = ++current->curr_ret_depth;
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index da1710499698..2308c0a2fd29 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -1595,12 +1595,15 @@ static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end)
unsigned long ftrace_location_range(unsigned long start, unsigned long end)
{
struct dyn_ftrace *rec;
+ unsigned long ip = 0;
+ rcu_read_lock();
rec = lookup_rec(start, end);
if (rec)
- return rec->ip;
+ ip = rec->ip;
+ rcu_read_unlock();
- return 0;
+ return ip;
}
/**
@@ -1614,25 +1617,22 @@ unsigned long ftrace_location_range(unsigned long start, unsigned long end)
*/
unsigned long ftrace_location(unsigned long ip)
{
- struct dyn_ftrace *rec;
+ unsigned long loc;
unsigned long offset;
unsigned long size;
- rec = lookup_rec(ip, ip);
- if (!rec) {
+ loc = ftrace_location_range(ip, ip);
+ if (!loc) {
if (!kallsyms_lookup_size_offset(ip, &size, &offset))
goto out;
/* map sym+0 to __fentry__ */
if (!offset)
- rec = lookup_rec(ip, ip + size - 1);
+ loc = ftrace_location_range(ip, ip + size - 1);
}
- if (rec)
- return rec->ip;
-
out:
- return 0;
+ return loc;
}
/**
@@ -2538,7 +2538,6 @@ ftrace_find_unique_ops(struct dyn_ftrace *rec)
/* Protected by rcu_tasks for reading, and direct_mutex for writing */
static struct ftrace_hash __rcu *direct_functions = EMPTY_HASH;
static DEFINE_MUTEX(direct_mutex);
-int ftrace_direct_func_count;
/*
* Search the direct_functions hash to see if the given instruction pointer
@@ -4202,12 +4201,12 @@ static int
add_rec_by_index(struct ftrace_hash *hash, struct ftrace_glob *func_g,
int clear_filter)
{
- long index = simple_strtoul(func_g->search, NULL, 0);
+ long index;
struct ftrace_page *pg;
struct dyn_ftrace *rec;
/* The index starts at 1 */
- if (--index < 0)
+ if (kstrtoul(func_g->search, 0, &index) || --index < 0)
return 0;
do_for_each_ftrace_rec(pg, rec) {
@@ -5318,14 +5317,6 @@ ftrace_set_addr(struct ftrace_ops *ops, unsigned long *ips, unsigned int cnt,
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
-struct ftrace_direct_func {
- struct list_head next;
- unsigned long addr;
- int count;
-};
-
-static LIST_HEAD(ftrace_direct_funcs);
-
static int register_ftrace_function_nolock(struct ftrace_ops *ops);
/*
@@ -5366,6 +5357,13 @@ static void remove_direct_functions_hash(struct ftrace_hash *hash, unsigned long
}
}
+static void register_ftrace_direct_cb(struct rcu_head *rhp)
+{
+ struct ftrace_hash *fhp = container_of(rhp, struct ftrace_hash, rcu);
+
+ free_ftrace_hash(fhp);
+}
+
/**
* register_ftrace_direct - Call a custom trampoline directly
* for multiple functions registered in @ops
@@ -5464,10 +5462,8 @@ int register_ftrace_direct(struct ftrace_ops *ops, unsigned long addr)
out_unlock:
mutex_unlock(&direct_mutex);
- if (free_hash && free_hash != EMPTY_HASH) {
- synchronize_rcu_tasks();
- free_ftrace_hash(free_hash);
- }
+ if (free_hash && free_hash != EMPTY_HASH)
+ call_rcu_tasks(&free_hash->rcu, register_ftrace_direct_cb);
if (new_hash)
free_ftrace_hash(new_hash);
@@ -5817,9 +5813,8 @@ __setup("ftrace_graph_notrace=", set_graph_notrace_function);
static int __init set_graph_max_depth_function(char *str)
{
- if (!str)
+ if (!str || kstrtouint(str, 0, &fgraph_max_depth))
return 0;
- fgraph_max_depth = simple_strtoul(str, NULL, 0);
return 1;
}
__setup("ftrace_graph_max_depth=", set_graph_max_depth_function);
@@ -6596,6 +6591,8 @@ static int ftrace_process_locs(struct module *mod,
/* We should have used all pages unless we skipped some */
if (pg_unuse) {
WARN_ON(!skipped);
+ /* Need to synchronize with ftrace_location_range() */
+ synchronize_rcu();
ftrace_free_pages(pg_unuse);
}
return ret;
@@ -6809,6 +6806,9 @@ void ftrace_release_mod(struct module *mod)
out_unlock:
mutex_unlock(&ftrace_lock);
+ /* Need to synchronize with ftrace_location_range() */
+ if (tmp_page)
+ synchronize_rcu();
for (pg = tmp_page; pg; pg = tmp_page) {
/* Needs to be called outside of ftrace_lock */
@@ -7142,6 +7142,7 @@ void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
unsigned long start = (unsigned long)(start_ptr);
unsigned long end = (unsigned long)(end_ptr);
struct ftrace_page **last_pg = &ftrace_pages_start;
+ struct ftrace_page *tmp_page = NULL;
struct ftrace_page *pg;
struct dyn_ftrace *rec;
struct dyn_ftrace key;
@@ -7183,12 +7184,8 @@ void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
ftrace_update_tot_cnt--;
if (!pg->index) {
*last_pg = pg->next;
- if (pg->records) {
- free_pages((unsigned long)pg->records, pg->order);
- ftrace_number_of_pages -= 1 << pg->order;
- }
- ftrace_number_of_groups--;
- kfree(pg);
+ pg->next = tmp_page;
+ tmp_page = pg;
pg = container_of(last_pg, struct ftrace_page, next);
if (!(*last_pg))
ftrace_pages = pg;
@@ -7205,6 +7202,11 @@ void ftrace_free_mem(struct module *mod, void *start_ptr, void *end_ptr)
clear_func_from_hashes(func);
kfree(func);
}
+ /* Need to synchronize with ftrace_location_range() */
+ if (tmp_page) {
+ synchronize_rcu();
+ ftrace_free_pages(tmp_page);
+ }
}
void __init ftrace_free_init_mem(void)
diff --git a/kernel/trace/trace_benchmark.c b/kernel/trace/trace_benchmark.c
index 811b08439406..e19c32f2a938 100644
--- a/kernel/trace/trace_benchmark.c
+++ b/kernel/trace/trace_benchmark.c
@@ -104,7 +104,7 @@ static void trace_do_benchmark(void)
stddev = 0;
delta = bm_total;
- delta = div64_u64(delta, bm_cnt);
+ do_div(delta, (u32)bm_cnt);
avg = delta;
if (stddev > 0) {