From 37314363cd65d19c71bea5f222e5108c93dc3c78 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sat, 8 Mar 2014 08:01:19 -0800 Subject: [PATCH] pkt_sched: move the sanity test in qdisc_list_add() The WARN_ON(root == &noop_qdisc)) added in qdisc_list_add() can trigger in normal conditions when devices are not up. It should be done only right before the list_add_tail() call. Fixes: e57a784d8cae4 ("pkt_sched: set root qdisc before change() in attach_default_qdiscs()") Reported-by: Valdis Kletnieks Tested-by: Mirco Tischler Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/sched/sch_api.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/net/sched/sch_api.c b/net/sched/sch_api.c index 1313145e3b86..a07d55e75698 100644 --- a/net/sched/sch_api.c +++ b/net/sched/sch_api.c @@ -273,11 +273,12 @@ 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; + if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) { + struct Qdisc *root = qdisc_dev(q)->qdisc; - WARN_ON_ONCE(root == &noop_qdisc); - if ((q->parent != TC_H_ROOT) && !(q->flags & TCQ_F_INGRESS)) + WARN_ON_ONCE(root == &noop_qdisc); list_add_tail(&q->list, &root->list); + } } EXPORT_SYMBOL(qdisc_list_add); -- 2.20.1