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Commit 6ea41d25 authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

clocksource: Call clocksource_change_rating() outside of watchdog_lock 



The changes to the watchdog logic introduced a lock inversion between
watchdog_lock and clocksource_mutex. Change the rating outside of
watchdog_lock to avoid it.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent 23970e38

kernel/time/clocksource.c

+9 −2
Original line number Diff line number Diff line
@@ -307,16 +307,23 @@ static void clocksource_watchdog_work(struct work_struct *work) 
{

	struct clocksource *cs, *tmp;

	unsigned long flags;

	LIST_HEAD(unstable);



	spin_lock_irqsave(&watchdog_lock, flags);

	list_for_each_entry_safe(cs, tmp, &watchdog_list, wd_list)

		if (cs->flags & CLOCK_SOURCE_UNSTABLE) {

			list_del_init(&cs->wd_list);

			clocksource_change_rating(cs, 0);

			list_add(&cs->wd_list, &unstable);

		}

	/* Check if the watchdog timer needs to be stopped. */

	clocksource_stop_watchdog();

	spin_unlock(&watchdog_lock);

	spin_unlock_irqrestore(&watchdog_lock, flags);



	/* Needs to be done outside of watchdog lock */

	list_for_each_entry_safe(cs, tmp, &unstable, wd_list) {

		list_del_init(&cs->wd_list);

		clocksource_change_rating(cs, 0);

	}

}



#else /* CONFIG_CLOCKSOURCE_WATCHDOG */