net_sched: fix order of queue length updates in qdisc_replace()
authorKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Sat, 19 Aug 2017 12:37:07 +0000 (15:37 +0300)
committerDavid S. Miller <davem@davemloft.net>
Mon, 21 Aug 2017 03:02:00 +0000 (20:02 -0700)
commit68a66d149a8c78ec6720f268597302883e48e9fa
treef387dd6f84d75bb14d89584ba7246cc8be245aed
parent49bf4b36fdee4db3c8bc0507a8413a93a8c711cf
net_sched: fix order of queue length updates in qdisc_replace()

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>
include/net/sch_generic.h