Commit-ID: 542e72fc90f5ed9eecb574f80f70868c7f296093 Gitweb: http://git.kernel.org/tip/542e72fc90f5ed9eecb574f80f70868c7f296093 Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> AuthorDate: Wed, 26 Jan 2011 15:38:35 +0100 Committer: Ingo Molnar <mingo@xxxxxxx> CommitDate: Thu, 3 Feb 2011 12:15:46 +0100 perf: Fix reading in perf_event_read() It is quite possible for the event to have been disabled between perf_event_read() sending the IPI and the CPU servicing the IPI and calling __perf_event_read(), hence revalidate the state. Reported-by: Stephane Eranian <eranian@xxxxxxxxxx> Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@xxxxxxx> --- kernel/perf_event.c | 7 ++++--- 1 files changed, 4 insertions(+), 3 deletions(-) diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 852ae8c..999835b 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -1901,11 +1901,12 @@ static void __perf_event_read(void *info) return; raw_spin_lock(&ctx->lock); - update_context_time(ctx); + if (ctx->is_active) + update_context_time(ctx); update_event_times(event); + if (event->state == PERF_EVENT_STATE_ACTIVE) + event->pmu->read(event); raw_spin_unlock(&ctx->lock); - - event->pmu->read(event); } static inline u64 perf_event_count(struct perf_event *event) -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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