--- zzzz-none-000/linux-2.6.32.61/net/sched/sch_tbf.c	2013-06-10 09:43:48.000000000 +0000
+++ ar10-7272-687/linux-2.6.32.61/net/sched/sch_tbf.c	2010-10-21 13:05:45.000000000 +0000
@@ -273,7 +273,7 @@
 	if (max_size < 0)
 		goto done;
 
-	if (qopt->limit > 0) {
+	if (qopt->limit > 0 && q->qdisc == &noop_qdisc) {
 		child = fifo_create_dflt(sch, &bfifo_qdisc_ops, qopt->limit);
 		if (IS_ERR(child)) {
 			err = PTR_ERR(child);