perf: Fix tear-down of inherited group events

[ upstream commit 38b435b16c36b0d863efcf3f07b34a6fac9873fd ] When destroying inherited events, we need to destroy groups too, otherwise the event iteration in perf_event_exit_task_context() will miss group siblings and we leak events with all the consequences. Reported-and-tested-by: Vince Weaver <[email protected]> Signed-off-by: Peter Zijlstra <[email protected]> Signed-off-by: Andi Kleen <[email protected]> Cc: <[email protected]> # .35+ LKML-Reference: <1300196470.2203.61.camel@twins> Signed-off-by: Ingo Molnar <[email protected]>
preludedrew · May 12, 2011 · 25c423d · 25c423d
1 parent fd89631
commit 25c423d
Showing 1 changed file with 8 additions and 5 deletions.
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
@@ -5391,17 +5391,20 @@ __perf_event_exit_task(struct perf_event *child_event,
 			 struct perf_event_context *child_ctx,
 			 struct task_struct *child)
 {
-	struct perf_event *parent_event;
+	if (child_event->parent) {
+		raw_spin_lock_irq(&child_ctx->lock);
+		perf_group_detach(child_event);
+		raw_spin_unlock_irq(&child_ctx->lock);
+	}
 
 	perf_event_remove_from_context(child_event);
 
-	parent_event = child_event->parent;
 	/*
-	 * It can happen that parent exits first, and has events
+	 * It can happen that the parent exits first, and has events
 	 * that are still around due to the child reference. These
-	 * events need to be zapped - but otherwise linger.
+	 * events need to be zapped.
 	 */
-	if (parent_event) {
+	if (child_event->parent) {
 		sync_child_event(child_event, child);
 		free_event(child_event);
 	}