net_sched: Bug in netem reordering

[ Upstream commit eb10192447370f19a215a8c2749332afa1199d46 ]

Not now, but it looks you are correct. q->qdisc is NULL until another
additional qdisc is attached (beside tfifo). See 50612537e9ab2969312.
The following patch should work.

From: Hagen Paul Pfeifer <hagen@jauu.net>

netem: catch NULL pointer by updating the real qdisc statistic

Reported-by: Vijay Subramanian <subramanian.vijay@gmail.com>
Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index a4ab207..fd34012 100644 (file)
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -383,8 +383,8 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch)
                q->counter = 0;
 
                __skb_queue_head(&q->qdisc->q, skb);
-               q->qdisc->qstats.backlog += qdisc_pkt_len(skb);
-               q->qdisc->qstats.requeues++;
+               sch->qstats.backlog += qdisc_pkt_len(skb);
+               sch->qstats.requeues++;
                ret = NET_XMIT_SUCCESS;
        }