perf: Fix tear-down of inherited group events
authorPeter Zijlstra <a.p.zijlstra@chello.nl>
Tue, 15 Mar 2011 13:37:10 +0000 (14:37 +0100)
committerIngo Molnar <mingo@elte.hu>
Wed, 16 Mar 2011 13:04:14 +0000 (14:04 +0100)
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 <vweaver1@eecs.utk.edu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org> # .35+
LKML-Reference: <1300196470.2203.61.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
kernel/perf_event.c

index 533f71570736ce368a13301056c748d6aa74706c..3472bb1a070c4c2972e2c790da9fb9dd86e36488 100644 (file)
@@ -6722,17 +6722,20 @@ __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_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);
        }