diff --git a/kernel/timer.c b/kernel/timer.c
index be394af5bc22..d8decb8d46b0 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -747,16 +747,19 @@ EXPORT_SYMBOL(mod_timer_pending);
 static inline
 unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
 {
-	unsigned long expires_limit, mask;
+	unsigned long expires_limit, mask, now;
 	int bit;
 
 	expires_limit = expires;
 
-	if (timer->slack > -1)
+	if (timer->slack >= 0) {
 		expires_limit = expires + timer->slack;
-	else if (time_after(expires, jiffies)) /* auto slack: use 0.4% */
-		expires_limit = expires + (expires - jiffies)/256;
-
+	} else {
+		now = jiffies;
+		/* No slack, if already expired else auto slack 0.4% */
+		if (time_after(expires, now))
+			expires_limit = expires + (expires - now)/256;
+	}
 	mask = expires ^ expires_limit;
 	if (mask == 0)
 		return expires;