perf_events, trace: Fix perf_trace_destroy(), mutex went missing

Steve spotted I forgot to do the destroy under event_mutex.

Reported-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1274451913.1674.1707.camel@laptop>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 49c7abf2ba5c1fafce486293c6f95688e017c2ba..e6f65887842c9a91649550daee07c593c818f9b5 100644 (file)
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -132,8 +132,9 @@ void perf_trace_destroy(struct perf_event *p_event)
        struct ftrace_event_call *tp_event = p_event->tp_event;
        int i;
 
+       mutex_lock(&event_mutex);
        if (--tp_event->perf_refcount > 0)
-               return;
+               goto out;
 
        if (tp_event->class->reg)
                tp_event->class->reg(tp_event, TRACE_REG_PERF_UNREGISTER);
@@ -157,6 +158,8 @@ void perf_trace_destroy(struct perf_event *p_event)
                        perf_trace_buf[i] = NULL;
                }
        }
+out:
+       mutex_unlock(&event_mutex);
 }
 
 __kprobes void *perf_trace_buf_prepare(int size, unsigned short type,