lkml.org 
[lkml]   [2012]   [Dec]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[tip:core/urgent] watchdog: Fix CPU hotplug regression
Commit-ID:  8d4516904b39507458bee8115793528e12b1d8dd
Gitweb: http://git.kernel.org/tip/8d4516904b39507458bee8115793528e12b1d8dd
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Tue, 4 Dec 2012 18:59:34 +0100
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Tue, 4 Dec 2012 19:56:59 +0100

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 dd4b80a..c8c21be 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 */

\
 
 \ /
  Last update: 2012-12-04 21:01    [W:0.101 / U:1.140 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site