perf: Fix tear-down of inherited group events
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>
diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 533f715..3472bb1 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -6722,17 +6722,20 @@
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);
}