From 7861144b8cb217634d738e94a748deeae139a1e2 Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@linux-foundation.org>
Date: Fri, 18 Apr 2014 15:07:12 -0700
Subject: [PATCH] kernel/watchdog.c:touch_softlockup_watchdog(): use
raw_cpu_write()
Fix:
BUG: using __this_cpu_write() in preemptible [00000000] code: systemd-udevd/497
caller is __this_cpu_preempt_check+0x13/0x20
CPU: 3 PID: 497 Comm: systemd-udevd Tainted: G W 3.15.0-rc1 #9
Hardware name: Hewlett-Packard HP EliteBook 8470p/179B, BIOS 68ICF Ver. F.02 04/27/2012
Call Trace:
check_preemption_disabled+0xe1/0xf0
__this_cpu_preempt_check+0x13/0x20
touch_nmi_watchdog+0x28/0x40
Reported-by: Luis Henriques <luis.henriques@canonical.com>
Tested-by: Luis Henriques <luis.henriques@canonical.com>
Cc: Eric Piel <eric.piel@tremplin-utc.net>
Cc: Robert Moore <robert.moore@intel.com>
Cc: Lv Zheng <lv.zheng@intel.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
kernel/watchdog.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index e90089fd78e0..516203e665fc 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -138,7 +138,11 @@ static void __touch_watchdog(void)
void touch_softlockup_watchdog(void)
{
- __this_cpu_write(watchdog_touch_ts, 0);
+ /*
+ * Preemption can be enabled. It doesn't matter which CPU's timestamp
+ * gets zeroed here, so use the raw_ operation.
+ */
+ raw_cpu_write(watchdog_touch_ts, 0);
}
EXPORT_SYMBOL(touch_softlockup_watchdog);