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Subject: Re: ftrace/perf_event leak
From: Peter Zijlstra <peterz@infradead.org>
To: Avi Kivity <avi@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>, Frederic Weisbecker <fweisbec@gmail.com>,
	Steven Rostedt <rostedt@goodmis.org>, kvm-devel <kvm@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Date: Wed, 01 Sep 2010 11:04:28 +0200
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diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index 000e6e8..35051f2 100644
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -88,10 +88,11 @@ int perf_trace_init(struct perf_event *p_event)
 	mutex_lock(&event_mutex);
 	list_for_each_entry(tp_event, &ftrace_events, list) {
 		if (tp_event->event.type == event_id &&
-		    tp_event->class && tp_event->class->reg &&
-		    try_module_get(tp_event->mod)) {
-			ret = perf_trace_event_init(tp_event, p_event);
-			break;
+		    tp_event->class && tp_event->class->reg) {
+		    	if (try_module_get(tp_event->mod)) {
+				ret = perf_trace_event_init(tp_event, p_event);
+				break;
+			}
 		}
 	}
 	mutex_unlock(&event_mutex);
@@ -138,6 +139,7 @@ void perf_trace_destroy(struct perf_event *p_event)
 
 	free_percpu(tp_event->perf_events);
 	tp_event->perf_events = NULL;
+	module_put(tp_event->mod);
 
 	if (!--total_ref_count) {
 		for (i = 0; i < 4; i++) {