From: Peter Zijlstra <a.p.zijls...@chello.nl>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    http://git.kernel.org/?p=linux/kernel/git/paulg/longterm-queue-2.6.34.git
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit 38b435b16c36b0d863efcf3f07b34a6fac9873fd upstream.

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 <vweav...@eecs.utk.edu>
Signed-off-by: Peter Zijlstra <a.p.zijls...@chello.nl>
LKML-Reference: <1300196470.2203.61.camel@twins>
Signed-off-by: Ingo Molnar <mi...@elte.hu>
Signed-off-by: Paul Gortmaker <paul.gortma...@windriver.com>
---
 kernel/perf_event.c | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 0e4499e..30e164e 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -5196,17 +5196,20 @@ __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);
        }
-- 
1.7.12.1

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