From 7dd47617114921fdd8c095509e5e7b4373cc44a1 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 26 Mar 2019 22:51:02 +0100 Subject: [PATCH] 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: 9cf57731b63e ("watchdog/softlockup: Replace "watchdog/%u" threads with cpu_stop_work") Reported-by: Maxime Coquelin Signed-off-by: Thomas Gleixner Tested-by: Maxime Coquelin Cc: Peter Zijlstra Cc: Oleg Nesterov Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Don Zickus Cc: Ricardo Neri Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/alpine.DEB.2.21.1903262245490.1789@nanos.tec.linutronix.de --- kernel/watchdog.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 403c9bd90413..6a5787233113 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -554,13 +554,15 @@ static void softlockup_start_all(void) int lockup_detector_online_cpu(unsigned int cpu) { - watchdog_enable(cpu); + if (cpumask_test_cpu(cpu, &watchdog_allowed_mask)) + watchdog_enable(cpu); return 0; } int lockup_detector_offline_cpu(unsigned int cpu) { - watchdog_disable(cpu); + if (cpumask_test_cpu(cpu, &watchdog_allowed_mask)) + watchdog_disable(cpu); return 0; }