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>