From 8d4516904b39507458bee8115793528e12b1d8dd Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 4 Dec 2012 18:59:34 +0100 Subject: [PATCH] watchdog: Fix CPU hotplug regression Norbert reported: "3.7-rc6 booted with nmi_watchdog=0 fails to suspend to RAM or offline CPUs. It's reproducable with a KVM guest and physical system." The reason is that commit bcd951cf(watchdog: Use hotplug thread infrastructure) missed to take this into account. So the cpu offline code gets stuck in the teardown function because it accesses non initialized data structures. Add a check for watchdog_enabled into that path to cure the issue. Reported-and-tested-by: Norbert Warmuth Tested-by: Joseph Salisbury Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1211231033230.2701@ionos Link: http://bugs.launchpad.net/bugs/1079534 Signed-off-by: Thomas Gleixner --- kernel/watchdog.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/kernel/watchdog.c b/kernel/watchdog.c index dd4b80a9f1a9..c8c21be11ab4 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -368,6 +368,9 @@ static void watchdog_disable(unsigned int cpu) { struct hrtimer *hrtimer = &__raw_get_cpu_var(watchdog_hrtimer); + if (!watchdog_enabled) + return; + watchdog_set_prio(SCHED_NORMAL, 0); hrtimer_cancel(hrtimer); /* disable the perf event */ -- 2.20.1