The queue limit check in netem_enqueue() uses q->t_len which only
counts packets in the internal tfifo. Packets placed in sch->q by
the reorder path (__qdisc_enqueue_head) are not counted, allowing
the total queue occupancy to exceed sch->limit under reordering.

Include sch->q.qlen in the limit check.

Fixes: 50612537e9ab ("netem: fix classful handling")
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Reviewed-by: Simon Horman <horms@kernel.org>
---
 net/sched/sch_netem.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 8ee72cac1faf..d400a730eadd 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c

@@ -524,7 +524,7 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 				1 << get_random_u32_below(8);
 	}
 
-	if (unlikely(q->t_len >= sch->limit)) {
+	if (unlikely(sch->q.qlen >= sch->limit)) {
 		/* re-link segs, so that qdisc_drop_all() frees them all */
 		skb->next = segs;
 		qdisc_drop_all(skb, sch, to_free);

-- 
2.53.0