[PATCH 5.3 130/140] net: netem: correct the parents backlog when corrupted packet was dropped

[Greg Kroah-Hartman]

From: Jakub Kicinski <jakub.kicinski@xxxxxxxxxxxxx>

[ 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@xxxxxxxxxxxxx>
Reviewed-by: Simon Horman <simon.horman@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/sched/sch_netem.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -616,6 +616,8 @@ 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;
 }