From 5600c7586ad9281dd2bf78cf46f8ad4353c75c9e Mon Sep 17 00:00:00 2001
From: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Date: Wed, 20 Sep 2017 15:45:36 +0300
Subject: net_sched: always reset qdisc backlog in qdisc_reset()

[ Upstream commit c8e1812960eeae42e2183154927028511c4bc566 ]

SKB stored in qdisc->gso_skb also counted into backlog.

Some qdiscs don't reset backlog to zero in ->reset(),
for example sfq just dequeue and free all queued skb.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Fixes: 2ccccf5fb43f ("net_sched: update hierarchical backlog too")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c
index 6cfb6e9..9016c8b 100644
--- a/net/sched/sch_generic.c
+++ b/net/sched/sch_generic.c
@@ -681,6 +681,7 @@ void qdisc_reset(struct Qdisc *qdisc)
 		qdisc->gso_skb = NULL;
 	}
 	qdisc->q.qlen = 0;
+	qdisc->qstats.backlog = 0;
 }
 EXPORT_SYMBOL(qdisc_reset);
 
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