perf: Fix perf_event_for_each() to use sibling

In perf_event_for_each() we call a function on an event, and then
iterate over the siblings of the event.

However we don't call the function on the siblings, we call it
repeatedly on the original event - it seems "obvious" that we should
be calling it with sibling as the argument.

It looks like this broke in commit 75f937f24bd9 ("Fix ctx->mutex
vs counter->mutex inversion").

The only effect of the bug is that the PERF_IOC_FLAG_GROUP parameter
to the ioctls doesn't work.

Signed-off-by: Michael Ellerman <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

diff --git a/kernel/events/core.c b/kernel/events/core.c
index a6a9ec4cd8f583d640ab0da9e4941b19fe8fd990..fd126f82b57cc77db01c5fd42e3e30b230d98a30 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3183,7 +3183,7 @@ static void perf_event_for_each(struct perf_event *event,
        perf_event_for_each_child(event, func);
        func(event);
        list_for_each_entry(sibling, &event->sibling_list, group_entry)
-               perf_event_for_each_child(event, func);
+               perf_event_for_each_child(sibling, func);
        mutex_unlock(&ctx->mutex);
 }