From: Jakub Kicinski <jakub.kicinski@netronome.com>
Date: Fri, 18 Oct 2019 16:16:58 +0000 (-0700)
Subject: net: netem: correct the parent's backlog when corrupted packet was dropped
X-Git-Tag: v4.9.212~54
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=37b41ca445947ab520fff9fecdb5163c5c3d1e98;p=thirdparty%2Fkernel%2Fstable.git

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 11c4c93f5ded7..e06491314d592 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -609,6 +609,8 @@ 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;
 }