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| author | Namhyung Kim <namhyung@kernel.org> | 2022-03-28 13:01:12 -0700 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-04-05 09:59:44 +0200 |
| commit | e3265a4386428d3d157d9565bb520aabff8b4bf0 (patch) | |
| tree | 16571db614fc109c9f9bfa7b0bda5168637b66c3 /kernel | |
| parent | ad4878d4d71d9ada913be2ad5b6d7f526a695b6f (diff) | |
| download | lwn-e3265a4386428d3d157d9565bb520aabff8b4bf0.tar.gz lwn-e3265a4386428d3d157d9565bb520aabff8b4bf0.zip | |
perf/core: Inherit event_caps
It was reported that some perf event setup can make fork failed on
ARM64. It was the case of a group of mixed hw and sw events and it
failed in perf_event_init_task() due to armpmu_event_init().
The ARM PMU code checks if all the events in a group belong to the
same PMU except for software events. But it didn't set the event_caps
of inherited events and no longer identify them as software events.
Therefore the test failed in a child process.
A simple reproducer is:
$ perf stat -e '{cycles,cs,instructions}' perf bench sched messaging
# Running 'sched/messaging' benchmark:
perf: fork(): Invalid argument
The perf stat was fine but the perf bench failed in fork(). Let's
inherit the event caps from the parent.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20220328200112.457740-1-namhyung@kernel.org
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/events/core.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/events/core.c b/kernel/events/core.c index cfde994ce61c..3980efcf931d 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -11635,6 +11635,9 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, event->state = PERF_EVENT_STATE_INACTIVE; + if (parent_event) + event->event_caps = parent_event->event_caps; + if (event->attr.sigtrap) atomic_set(&event->event_limit, 1); |