[PATCH 3.16 081/136] net: netem: correct the parent's backlog when corrupted packet was dropped

Ben Hutchings
2019-12-17T00:55:39Z

From: Jakub Kicinski <jakub.kicinski@netronome.com>

commit e0ad032e144731a5928f2d75e91c2064ba1a764c upstream.

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: Ben Hutchings <ben@decadent.org.uk>
---
net/sched/sch_netem.c | 2 ++
1 file changed, 2 insertions(+)

--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -599,6 +599,8 @@ 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;
}