From 558e6547e4b8a2b13608a24a9d3679802f91c4c7 Mon Sep 17 00:00:00 2001
From: Li Zefan <lizf@cn.fujitsu.com>
Date: Mon, 24 Aug 2009 12:19:47 +0800
Subject: [PATCH] tracing/profile: fix profile_disable vs module_unload
If the correspoding module is unloaded before ftrace_profile_disable()
is called, event->profile_disable() won't be called, which can
cause oops:
# insmod trace-events-sample.ko
# perf record -f -a -e sample:foo_bar sleep 3 &
# sleep 1
# rmmod trace_events_sample
# insmod trace-events-sample.ko
OOPS!
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
LKML-Reference: <4A9214E3.2070807@cn.fujitsu.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
---
kernel/trace/trace_event_profile.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/trace_event_profile.c b/kernel/trace/trace_event_profile.c
index 11ba5bb4ed0a..55a25c933d15 100644
--- a/kernel/trace/trace_event_profile.c
+++ b/kernel/trace/trace_event_profile.c
@@ -5,6 +5,7 @@
*
*/
+#include <linux/module.h>
#include "trace.h"
int ftrace_profile_enable(int event_id)
@@ -14,7 +15,8 @@ int ftrace_profile_enable(int event_id)
mutex_lock(&event_mutex);
list_for_each_entry(event, &ftrace_events, list) {
- if (event->id == event_id && event->profile_enable) {
+ if (event->id == event_id && event->profile_enable &&
+ try_module_get(event->mod)) {
ret = event->profile_enable(event);
break;
}
@@ -32,6 +34,7 @@ void ftrace_profile_disable(int event_id)
list_for_each_entry(event, &ftrace_events, list) {
if (event->id == event_id) {
event->profile_disable(event);
+ module_put(event->mod);
break;
}
}
--
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