perf: Fix EXIT event notification (524eff18) · Commits · 戴 / test

The perf_event_task_ctx() function needs to be called with preemption disabled, since it's checking for currently scheduled cpu against event cpu. We disable preemption for task related perf event context if there's one defined, leaving up to the chance which cpu it gets scheduled in. Signed-off-by:

Jiri Olsa <jolsa@redhat.com> Acked-by:

Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Stephane Eranian <eranian@google.com> Cc: Borislav Petkov <bp@alien8.de> Link: http://lkml.kernel.org/r/1367857638-27631-2-git-send-email-jolsa@redhat.com Signed-off-by:

Ingo Molnar <mingo@kernel.org>

kernel/events/core.c

+14 −12

Original line number	Diff line number	Diff line
		@@ -4474,7 +4474,7 @@ static void perf_event_task_ctx(struct perf_event_context *ctx,
		static void perf_event_task_event(struct perf_task_event *task_event)
		{
		struct perf_cpu_context *cpuctx;
		struct perf_event_context *ctx;
		struct perf_event_context ctx, task_ctx = task_event->task_ctx;
		struct pmu *pmu;
		int ctxn;

		@@ -4485,20 +4485,22 @@ static void perf_event_task_event(struct perf_task_event *task_event)
		goto next;
		perf_event_task_ctx(&cpuctx->ctx, task_event);

		ctx = task_event->task_ctx;
		if (!ctx) {
		if (task_ctx)
		goto next;
		ctxn = pmu->task_ctx_nr;
		if (ctxn < 0)
		goto next;
		ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
		if (ctx)
		perf_event_task_ctx(ctx, task_event);
		}
		next:
		put_cpu_ptr(pmu->pmu_cpu_context);
		}
		if (task_event->task_ctx)
		perf_event_task_ctx(task_event->task_ctx, task_event);
		if (task_ctx) {
		preempt_disable();
		perf_event_task_ctx(task_ctx, task_event);
		preempt_enable();
		}

		rcu_read_unlock();
		}

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