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: Thomas Gleixner <tglx@linutronix.de>

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index a1657b5..02dc22d 100644 (file)
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -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 */