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Commit b43cb43c authored by Ulrich Obergfell's avatar Ulrich Obergfell Committed by Linus Torvalds
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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: default avatarUlrich Obergfell <uobergfe@redhat.com>
Reviewed-by: default avatarAaron Tomlin <atomlin@redhat.com>
Acked-by: default avatarDon Zickus <dzickus@redhat.com>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 58cf690a

kernel/watchdog.c

+23 −7
Original line number Diff line number Diff line
@@ -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)
@@ -753,8 +760,16 @@ 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);