tree 0731370394acb339b7469408cad02d865128f199
parent 3e00bf91fefced104ba91721674efe4502cb416a
author Konstantin Khlebnikov <khlebnikov@yandex-team.ru> 1503146227 +0300
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1504081302 +0200

net_sched: fix order of queue length updates in qdisc_replace()


[ Upstream commit 68a66d149a8c78ec6720f268597302883e48e9fa ]

This important to call qdisc_tree_reduce_backlog() after changing queue
length. Parent qdisc should deactivate class in ->qlen_notify() called from
qdisc_tree_reduce_backlog() but this happens only if qdisc->q.qlen in zero.

Missed class deactivations leads to crashes/warnings at picking packets
from empty qdisc and corrupting state at reactivating this class in future.

Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Fixes: 86a7996cc8a0 ("net_sched: introduce qdisc_replace() helper")
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>