From e57a784d8cae429f5b697fe55abf420181d9ff09 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 12 Dec 2013 15:41:56 -0800 Subject: [PATCH] pkt_sched: set root qdisc before change() in attach_default_qdiscs() After commit 95dc19299f74 ("pkt_sched: give visibility to mq slave qdiscs") we call disc_list_add() while the device qdisc might be the noop_qdisc one. This shows up as duplicates in "tc qdisc show", as all inactive devices point to noop_qdisc. Fix this by setting dev->qdisc to the new qdisc before calling ops->change() in attach_default_qdiscs() Add a WARN_ON_ONCE() to catch any future similar problem. Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/sched/sch_api.c | 5 ++++- net/sched/sch_generic.c | 2 +- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index 547b4a8..c31190e 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -273,8 +273,11 @@ static struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle) void qdisc_list_add(struct Qdisc *q) { + struct Qdisc *root = qdisc_dev(q)->qdisc; + + WARN_ON_ONCE(root == &noop_qdisc); if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) - list_add_tail(&q->list, &qdisc_dev(q)->qdisc->list); + list_add_tail(&q->list, &root->list); } EXPORT_SYMBOL(qdisc_list_add); diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 6a91d7d..32bb942 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -718,8 +718,8 @@ static void attach_default_qdiscs(struct net_device *dev) } else { qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT); if (qdisc) { - qdisc->ops->attach(qdisc); dev->qdisc = qdisc; + qdisc->ops->attach(qdisc); } } } -- 2.7.4