netdev - [PATCH net v2 2/2] net: netem: correct the parent's backlog when corrupted packet was dropped

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Date:   Fri, 18 Oct 2019 09:16:58 -0700
From:   Jakub Kicinski <jakub.kicinski@...ronome.com>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org, oss-drivers@...ronome.com,
        stephen@...workplumber.org, xiyou.wangcong@...il.com,
        Jakub Kicinski <jakub.kicinski@...ronome.com>,
        Simon Horman <simon.horman@...ronome.com>
Subject: [PATCH net v2 2/2] net: netem: correct the parent's backlog when corrupted packet was dropped

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@...ronome.com>
Reviewed-by: Simon Horman <simon.horman@...ronome.com>
---
 net/sched/sch_netem.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/sched/sch_netem.c b/net/sched/sch_netem.c
index 942eb17f413c..42e557d48e4e 100644
--- a/net/sched/sch_netem.c
+++ b/net/sched/sch_netem.c
@@ -616,6 +616,8 @@ static int netem_enqueue(struct sk_buff *skb, struct Qdisc *sch,
 		}
 		/* 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;
 }
-- 
2.23.0