From fe8e5b5a60f8427940d33b205e127aecfb0bca10 Mon Sep 17 00:00:00 2001
From: Frederic Weisbecker <fweisbec@gmail.com>
Date: Sat, 3 Oct 2009 14:55:18 +0200
Subject: [PATCH] tracing: Check total refcount before releasing bufs in
profile_enable failure
When we call the profile_enable() callback of an event, we release the
shared perf event tracing buffers unconditionnaly in the failure path.
This is wrong because there may be other users of these. Then check the
total refcount before doing this.
Reported-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Li Zefan <lizf@cn.fujitsu.com>
---
kernel/trace/trace_event_profile.c | 15 ++++++++++-----
1 file changed, 10 insertions(+), 5 deletions(-)
diff --git a/kernel/trace/trace_event_profile.c b/kernel/trace/trace_event_profile.c
index dd44b8768867..e52784b7b844 100644
--- a/kernel/trace/trace_event_profile.c
+++ b/kernel/trace/trace_event_profile.c
@@ -31,7 +31,7 @@ static int ftrace_profile_enable_event(struct ftrace_event_call *event)
if (atomic_inc_return(&event->profile_count))
return 0;
- if (!total_profile_count++) {
+ if (!total_profile_count) {
buf = (char *)alloc_percpu(profile_buf_t);
if (!buf)
goto fail_buf;
@@ -46,14 +46,19 @@ static int ftrace_profile_enable_event(struct ftrace_event_call *event)
}
ret = event->profile_enable();
- if (!ret)
+ if (!ret) {
+ total_profile_count++;
return 0;
+ }
- kfree(trace_profile_buf_nmi);
fail_buf_nmi:
- kfree(trace_profile_buf);
+ if (!total_profile_count) {
+ kfree(trace_profile_buf_nmi);
+ kfree(trace_profile_buf);
+ trace_profile_buf_nmi = NULL;
+ trace_profile_buf = NULL;
+ }
fail_buf:
- total_profile_count--;
atomic_dec(&event->profile_count);
return ret;
--
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