--- zzzz-none-000/linux-3.10.107/net/sched/sch_sfq.c	2017-06-27 09:49:32.000000000 +0000
+++ vr9-7490-729/linux-3.10.107/net/sched/sch_sfq.c	2021-11-10 11:53:56.000000000 +0000
@@ -506,8 +506,9 @@
 	struct sfq_slot *slot;
 
 	/* No active slots */
-	if (q->tail == NULL)
+	if (q->cur_depth == 0) {
 		return NULL;
+	}
 
 next_slot:
 	a = q->tail->next;