perf: Fix 'perf sched record' deadlock (8bb39f9a) · Commits · 戴 / test

perf sched record can deadlock a box should the holder of handle->data->lock take an interrupt, and then attempt to acquire an rq lock held by a CPU trying to acquire the same lock. Disable interrupts. CPU0 CPU1 sched event with rq->lock held grab handle->data->lock spin on handle->data->lock interrupt try to grab rq->lock Reported-by:

Li Zefan <lizf@cn.fujitsu.com> Signed-off-by:

Mike Galbraith <efault@gmx.de> Tested-by:

Li Zefan <lizf@cn.fujitsu.com> Signed-off-by:

Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <1269598293.6174.8.camel@marge.simson.net> Signed-off-by:

Ingo Molnar <mingo@elte.hu>

kernel/perf_event.c

+12 −3

Original line number	Diff line number	Diff line
		@@ -3376,15 +3376,23 @@ static void perf_event_task_output(struct perf_event *event,
		struct perf_task_event *task_event)
		{
		struct perf_output_handle handle;
		int size;
		struct task_struct *task = task_event->task;
		int ret;
		unsigned long flags;
		int size, ret;

		/*
		* If this CPU attempts to acquire an rq lock held by a CPU spinning
		* in perf_output_lock() from interrupt context, it's game over.
		*/
		local_irq_save(flags);

		size = task_event->event_id.header.size;
		ret = perf_output_begin(&handle, event, size, 0, 0);

		if (ret)
		if (ret) {
		local_irq_restore(flags);
		return;
		}

		task_event->event_id.pid = perf_event_pid(event, task);
		task_event->event_id.ppid = perf_event_pid(event, current);
		@@ -3395,6 +3403,7 @@ static void perf_event_task_output(struct perf_event *event,
		perf_output_put(&handle, task_event->event_id);

		perf_output_end(&handle);
		local_irq_restore(flags);
		}

		static int perf_event_task_match(struct perf_event *event)

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