perf: Ignore non-sampling overflows

Some arch implementations call perf_event_overflow() by 'accident',
ignore this.

Reported-by: Francis Moreau <francis.moro@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 7 insertions, 0 deletions

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 98c5549c8e29..af1e63f249f3 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -4240,6 +4240,13 @@ static int __perf_event_overflow(struct perf_event *event, int nmi,
         struct hw_perf_event *hwc = &event->hw;
         int ret = 0;
 
+        /*
+         * Non-sampling counters might still use the PMI to fold short
+         * hardware counters, ignore those.
+         */
+        if (unlikely(!is_sampling_event(event)))
+                return 0;
+
         if (!throttle) {
                 hwc->interrupts++;
         } else {