From b43cb43cb85b91d79d9f0719ff581e8cb6dfbb8f Mon Sep 17 00:00:00 2001 From: Ulrich Obergfell Date: Thu, 5 Nov 2015 18:44:33 -0800 Subject: [PATCH] watchdog: implement error handling in update_watchdog_all_cpus() and callers update_watchdog_all_cpus() now passes errors from watchdog_park_threads() up to functions in the call chain. This allows watchdog_enable_all_cpus() and proc_watchdog_update() to handle such errors too. Signed-off-by: Ulrich Obergfell Reviewed-by: Aaron Tomlin Acked-by: Don Zickus Cc: Ulrich Obergfell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- kernel/watchdog.c | 30 +++++++++++++++++++++++------- 1 file changed, 23 insertions(+), 7 deletions(-) diff --git a/kernel/watchdog.c b/kernel/watchdog.c index f0f8a78..704f933 100644 --- a/kernel/watchdog.c +++ b/kernel/watchdog.c @@ -731,10 +731,17 @@ void lockup_detector_resume(void) mutex_unlock(&watchdog_proc_mutex); } -static void update_watchdog_all_cpus(void) +static int update_watchdog_all_cpus(void) { - watchdog_park_threads(); + int ret; + + ret = watchdog_park_threads(); + if (ret) + return ret; + watchdog_unpark_threads(); + + return 0; } static int watchdog_enable_all_cpus(void) @@ -753,9 +760,17 @@ static int watchdog_enable_all_cpus(void) * Enable/disable the lockup detectors or * change the sample period 'on the fly'. */ - update_watchdog_all_cpus(); + err = update_watchdog_all_cpus(); + + if (err) { + watchdog_disable_all_cpus(); + pr_err("Failed to update lockup detectors, disabled\n"); + } } + if (err) + watchdog_enabled = 0; + return err; } @@ -851,12 +866,13 @@ static int proc_watchdog_common(int which, struct ctl_table *table, int write, } while (cmpxchg(&watchdog_enabled, old, new) != old); /* - * Update the run state of the lockup detectors. - * Restore 'watchdog_enabled' on failure. + * Update the run state of the lockup detectors. There is _no_ + * need to check the value returned by proc_watchdog_update() + * and to restore the previous value of 'watchdog_enabled' as + * both lockup detectors are disabled if proc_watchdog_update() + * returns an error. */ err = proc_watchdog_update(); - if (err) - watchdog_enabled = old; } out: mutex_unlock(&watchdog_proc_mutex); -- 2.7.4