| From | Ben Hutchings <> | Date | Wed, 15 Feb 2017 22:41:34 +0000 | Subject | [PATCH 3.2 110/126] perf: Fix perf_event_for_each() to use sibling |
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3.2.85-rc1 review patch. If anyone has any objections, please let me know.
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From: Michael Ellerman <michael@ellerman.id.au>
commit 724b6daa13e100067c30cfc4d1ad06629609dc4e upstream.
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 <michael@ellerman.id.au> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1334109253-31329-1-git-send-email-michael@ellerman.id.au Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- kernel/events/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3326,7 +3326,7 @@ static void perf_event_for_each(struct p 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); }
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