Messages in this thread Patch in this message | | | Date | Sat, 12 Sep 2009 23:05:46 -0400 | From | Steven Rostedt <> | Subject | [PATCH 3/4] tracing/profile: fix profile_disable vs module_unload |
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From: Li Zefan <lizf@cn.fujitsu.com>
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 files changed, 4 insertions(+), 1 deletions(-)
diff --git a/kernel/trace/trace_event_profile.c b/kernel/trace/trace_event_profile.c index 11ba5bb..55a25c9 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; } } -- 1.6.3.3 --
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