From: Gleb Natapov Date: Sun, 23 Oct 2011 17:10:33 +0000 (+0200) Subject: perf: Do not set task_ctx pointer in cpuctx if there are no events in the context X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=1d5f003f5a964711853514b04ddc872eec0fdc7b;p=openwrt%2Fstaging%2Fblogic.git perf: Do not set task_ctx pointer in cpuctx if there are no events in the context Do not set task_ctx pointer during sched_in if there are no events associated with the context. Otherwise if during task execution total number of events in the system will become zero perf_event_context_sched_out() will not be called and cpuctx->task_ctx will be left with a stale value. Signed-off-by: Gleb Natapov Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20111023171033.GI17571@redhat.com Signed-off-by: Ingo Molnar --- diff --git a/kernel/events/core.c b/kernel/events/core.c index 0e8457da6f95..b0c1186fd97b 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -2173,7 +2173,8 @@ static void perf_event_context_sched_in(struct perf_event_context *ctx, perf_event_sched_in(cpuctx, ctx, task); - cpuctx->task_ctx = ctx; + if (ctx->nr_events) + cpuctx->task_ctx = ctx; perf_pmu_enable(ctx->pmu); perf_ctx_unlock(cpuctx, ctx);