Messages in this thread Patch in this message | | | From | Michael Ellerman <> | Subject | [PATCH] perf: Fix perf_event_for_each() to use sibling | Date | Wed, 11 Apr 2012 11:54:13 +1000 |
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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> ---
This one seems so simple that I keep thinking I've missed something, I'm sure someone will tell me if I have ;)
AFAICS tools/perf never exercises this, ie. it always individually enables counters - which might explain how it could be broken and no one has noticed. --- kernel/events/core.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/kernel/events/core.c b/kernel/events/core.c index 1b5c081..b82121b 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -3097,7 +3097,7 @@ 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); } -- 1.7.5.4
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