Commit 7dd47617 authored Mar 26, 2019 by Thomas Gleixner

watchdog: Respect watchdog cpumask on CPU hotplug



The rework of the watchdog core to use cpu_stop_work broke the watchdog
cpumask on CPU hotplug.

The watchdog_enable/disable() functions are now called unconditionally from
the hotplug callback, i.e. even on CPUs which are not in the watchdog
cpumask. As a consequence the watchdog can become unstoppable.

Only invoke them when the plugged CPU is in the watchdog cpumask.

Fixes: 9cf57731 ("watchdog/softlockup: Replace "watchdog/%u" threads with cpu_stop_work")
Reported-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1903262245490.1789@nanos.tec.linutronix.de

parent 056d28d1

kernel/watchdog.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -554,12 +554,14 @@ static void softlockup_start_all(void)

		int lockup_detector_online_cpu(unsigned int cpu)
		{
		if (cpumask_test_cpu(cpu, &watchdog_allowed_mask))
		watchdog_enable(cpu);
		return 0;
		}

		int lockup_detector_offline_cpu(unsigned int cpu)
		{
		if (cpumask_test_cpu(cpu, &watchdog_allowed_mask))
		watchdog_disable(cpu);
		return 0;
		}

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