Merge tag 'perf-urgent-2020-10-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (aa5c3a29) · Commits · 戴 / test

Pull perf fix from Ingo Molnar: "Fix an error handling bug that can cause a lockup if a CPU is offline (doh ...)" * tag 'perf-urgent-2020-10-11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf: Fix task_function_call() error handling

kernel/events/core.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -99,7 +99,7 @@ static void remote_function(void *data)
		* retry due to any failures in smp_call_function_single(), such as if the
		* task_cpu() goes offline concurrently.
		*
		* returns @func return value or -ESRCH when the process isn't running
		* returns @func return value or -ESRCH or -ENXIO when the process isn't running
		*/
		static int
		task_function_call(struct task_struct p, remote_function_f func, void info)
		@@ -115,7 +115,8 @@ task_function_call(struct task_struct p, remote_function_f func, void info)
		for (;;) {
		ret = smp_call_function_single(task_cpu(p), remote_function,
		&data, 1);
		ret = !ret ? data.ret : -EAGAIN;
		if (!ret)
		ret = data.ret;

		if (ret != -EAGAIN)
		break;

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