The following commit has been merged into the perf/urgent branch of tip: Commit-ID: f3a519e4add93b7b31a6616f0b09635ff2e6a159 Gitweb: https://git.kernel.org/tip/f3a519e4add93b7b31a6616f0b09635ff2e6a159 Author: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> AuthorDate: Tue, 22 Oct 2019 10:39:40 +03:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Tue, 22 Oct 2019 14:39:37 +02:00 perf/aux: Fix AUX output stopping Commit: 8a58ddae2379 ("perf/core: Fix exclusive events' grouping") allows CAP_EXCLUSIVE events to be grouped with other events. Since all of those also happen to be AUX events (which is not the case the other way around, because arch/s390), this changes the rules for stopping the output: the AUX event may not be on its PMU's context any more, if it's grouped with a HW event, in which case it will be on that HW event's context instead. If that's the case, munmap() of the AUX buffer can't find and stop the AUX event, potentially leaving the last reference with the atomic context, which will then end up freeing the AUX buffer. This will then trip warnings: Fix this by using the context's PMU context when looking for events to stop, instead of the event's PMU context. Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx> Cc: Jiri Olsa <jolsa@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Stephane Eranian <eranian@xxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Vince Weaver <vincent.weaver@xxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Link: https://lkml.kernel.org/r/20191022073940.61814-1-alexander.shishkin@xxxxxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- kernel/events/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index f5d7950..bb3748d 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -6949,7 +6949,7 @@ static void __perf_event_output_stop(struct perf_event *event, void *data) static int __perf_pmu_output_stop(void *info) { struct perf_event *event = info; - struct pmu *pmu = event->pmu; + struct pmu *pmu = event->ctx->pmu; struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context); struct remote_output ro = { .rb = event->rb,
