Merge remote-tracking branch 'remotes/fslc/4.9-2.3.x-imx' into toradex_4.9-2.3.x-imx-next

Conflicts:
	sound/soc/codecs/sgtl5000.c
	sound/soc/fsl/imx-sgtl5000.c

1 files changed, 9 insertions, 2 deletions

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 7e4fad75acaa..2924ff544c9e 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -272,8 +272,15 @@ static void clocksource_watchdog(unsigned long data)
 	next_cpu = cpumask_next(raw_smp_processor_id(), cpu_online_mask);
 	if (next_cpu >= nr_cpu_ids)
 		next_cpu = cpumask_first(cpu_online_mask);
-	watchdog_timer.expires += WATCHDOG_INTERVAL;
-	add_timer_on(&watchdog_timer, next_cpu);
+
+	/*
+	 * Arm timer if not already pending: could race with concurrent
+	 * pair clocksource_stop_watchdog() clocksource_start_watchdog().
+	 */
+	if (!timer_pending(&watchdog_timer)) {
+		watchdog_timer.expires += WATCHDOG_INTERVAL;
+		add_timer_on(&watchdog_timer, next_cpu);
+	}
 out:
 	spin_unlock(&watchdog_lock);
 }