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Subject[PATCH 4/4] watchdog: fix race between proc_watchdog_thresh() and watchdog_timer_fn()
Date
Theoretically it is possible that the watchdog timer expires
right at the time when a user sets 'watchdog_thresh' to zero
(note: this disables the lockup detectors). In this scenario,
the is_softlockup() function - which is called by the timer -
could produce a false positive.

Fix this by checking the current value of 'watchdog_thresh'.

Signed-off-by: Ulrich Obergfell <uobergfe@redhat.com>
---
kernel/watchdog.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 84c4744..18f34cf 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -289,7 +289,7 @@ static int is_softlockup(unsigned long touch_ts)
{
unsigned long now = get_timestamp();

- if (watchdog_enabled & SOFT_WATCHDOG_ENABLED) {
+ if ((watchdog_enabled & SOFT_WATCHDOG_ENABLED) && watchdog_thresh){
/* Warn about unreasonable delays. */
if (time_after(now, touch_ts + get_softlockup_thresh()))
return now - touch_ts;
--
1.7.11.7


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