netem: fix a use after free
If the packet was dropped by lower qdisc, then we must not
access it later.
Save qdisc_pkt_len(skb) in a temp variable.
Fixes: 2ccccf5fb43f ("net_sched: update hierarchical backlog too")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 205bed0..178f163 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -650,14 +650,14 @@
#endif
if (q->qdisc) {
+ unsigned int pkt_len = qdisc_pkt_len(skb);
int err = qdisc_enqueue(skb, q->qdisc);
- if (unlikely(err != NET_XMIT_SUCCESS)) {
- if (net_xmit_drop_count(err)) {
- qdisc_qstats_drop(sch);
- qdisc_tree_reduce_backlog(sch, 1,
- qdisc_pkt_len(skb));
- }
+ if (err != NET_XMIT_SUCCESS &&
+ net_xmit_drop_count(err)) {
+ qdisc_qstats_drop(sch);
+ qdisc_tree_reduce_backlog(sch, 1,
+ pkt_len);
}
goto tfifo_dequeue;
}