diff --git a/[refs] b/[refs]
index 9954e9b42910..fd0b9d2b5cad 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: af39241b90a345556b8884adff87096afe71b050
+refs/heads/master: 6409c4da289d6905f7ae2bd0630438368439bda2
diff --git a/trunk/kernel/sched_clock.c b/trunk/kernel/sched_clock.c
index a0b0852414cc..db69174b1178 100644
--- a/trunk/kernel/sched_clock.c
+++ b/trunk/kernel/sched_clock.c
@@ -29,6 +29,7 @@
 #include <linux/spinlock.h>
 #include <linux/ktime.h>
 #include <linux/module.h>
+#include <linux/hardirq.h>
 
 /*
  * Scheduler clock - returns current time in nanosec units.
@@ -151,6 +152,13 @@ u64 sched_clock_cpu(int cpu)
 	struct sched_clock_data *scd = cpu_sdc(cpu);
 	u64 now, clock, this_clock, remote_clock;
 
+	/*
+	 * Normally this is not called in NMI context - but if it is,
+	 * trying to do any locking here is totally lethal.
+	 */
+	if (unlikely(in_nmi()))
+		return scd->clock;
+
 	if (unlikely(!sched_clock_running))
 		return 0ull;