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| author | Ulrich Obergfell <uobergfe@redhat.com> | 2015-11-05 18:44:56 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-11-05 19:34:48 -0800 |
| commit | 39d2da2161d35de301ec5397ce9103c68b883054 (patch) | |
| tree | 0a3608ff72cb3af0c5d66246cc8682dd8753404d /kernel/watchdog.c | |
| parent | a2a45b85ec45db4b041ea5d93b21033dbc3cc0fc (diff) | |
| download | lwn-39d2da2161d35de301ec5397ce9103c68b883054.tar.gz lwn-39d2da2161d35de301ec5397ce9103c68b883054.zip | |
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>
Diffstat (limited to 'kernel/watchdog.c')
| -rw-r--r-- | kernel/watchdog.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/watchdog.c b/kernel/watchdog.c index 84c4744d1977..18f34cf75f74 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; |