diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 9f06094..0c71885 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -489,6 +489,9 @@
 {
 	unsigned long delta_fair;
 
+	if (unlikely(!se->wait_start_fair))
+		return;
+
 	delta_fair = (unsigned long)min((u64)(2*sysctl_sched_runtime_limit),
 			(u64)(cfs_rq->fair_clock - se->wait_start_fair));