net: netem: correct the parent's backlog when corrupted packet was dropped

[ Upstream commit e0ad032e144731a5928f2d75e91c2064ba1a764c ]

If packet corruption failed we jump to finish_segs and return
NET_XMIT_SUCCESS. Seeing success will make the parent qdisc
increment its backlog, that's incorrect - we need to return
NET_XMIT_DROP.

Fixes: 6071bd1aa13e ("netem: Segment GSO packets on enqueue")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 7660aa5..014a28d 100644 (file)
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -607,6 +607,8 @@ finish_segs:
                }
                /* Parent qdiscs accounted for 1 skb of size @prev_len */
                qdisc_tree_reduce_backlog(sch, -(nb - 1), -(len - prev_len));
+       } else if (!skb) {
+               return NET_XMIT_DROP;
        }
        return NET_XMIT_SUCCESS;
 }