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authorKonstantin Khlebnikov <khlebnikov@yandex-team.ru>2017-08-19 15:37:07 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-08-30 10:21:42 +0200
commit7fa2fdf9f19e3b4bc71051c115271741369b5e7f (patch)
tree0731370394acb339b7469408cad02d865128f199
parent3e00bf91fefced104ba91721674efe4502cb416a (diff)
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>
-rw-r--r--include/net/sch_generic.h5
1 files changed, 4 insertions, 1 deletions
diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h
index e6aa0a249672..f18fc1a0321f 100644
--- a/include/net/sch_generic.h
+++ b/include/net/sch_generic.h
@@ -768,8 +768,11 @@ static inline struct Qdisc *qdisc_replace(struct Qdisc *sch, struct Qdisc *new,
old = *pold;
*pold = new;
if (old != NULL) {
- qdisc_tree_reduce_backlog(old, old->q.qlen, old->qstats.backlog);
+ unsigned int qlen = old->q.qlen;
+ unsigned int backlog = old->qstats.backlog;
+
qdisc_reset(old);
+ qdisc_tree_reduce_backlog(old, qlen, backlog);
}
sch_tree_unlock(sch);