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authorNamhyung Kim <namhyung@kernel.org>2022-03-28 23:01:12 +0300
committerPeter Zijlstra <peterz@infradead.org>2022-04-05 10:59:44 +0300
commite3265a4386428d3d157d9565bb520aabff8b4bf0 (patch)
tree16571db614fc109c9f9bfa7b0bda5168637b66c3 /kernel
parentad4878d4d71d9ada913be2ad5b6d7f526a695b6f (diff)
downloadlinux-e3265a4386428d3d157d9565bb520aabff8b4bf0.tar.xz
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.c3
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);