kernel/watchdog.c: fix race between proc_watchdog_thresh() and watchdog_timer_fn()
authorUlrich Obergfell <uobergfe@redhat.com>
Fri, 6 Nov 2015 02:44:56 +0000 (18:44 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 6 Nov 2015 03:34:48 +0000 (19:34 -0800)
commit39d2da2161d35de301ec5397ce9103c68b883054
tree0a3608ff72cb3af0c5d66246cc8682dd8753404d
parenta2a45b85ec45db4b041ea5d93b21033dbc3cc0fc
kernel/watchdog.c: fix race between proc_watchdog_thresh() and watchdog_timer_fn()

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>
Acked-by: Don Zickus <dzickus@redhat.com>
Reviewed-by: Aaron Tomlin <atomlin@redhat.com>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
kernel/watchdog.c