From 8d4516904b39507458bee8115793528e12b1d8dd Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
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 <nwarmuth@t-online.de>
Tested-by: Joseph Salisbury <joseph.salisbury@canonical.com>
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 <tglx@linutronix.de>
---
kernel/watchdog.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index dd4b80a9f1a98..c8c21be11ab48 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 */
--
2.30.2