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Commit e57a784d authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

pkt_sched: set root qdisc before change() in attach_default_qdiscs() 



After commit 95dc1929 ("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: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 59bcaed5

net/sched/sch_api.c

+4 −1
Original line number Original line Diff line number Diff line
@@ -273,8 +273,11 @@ static struct Qdisc *qdisc_match_from_root(struct Qdisc *root, u32 handle) 




void qdisc_list_add(struct Qdisc *q)

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))

	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);

EXPORT_SYMBOL(qdisc_list_add);

net/sched/sch_generic.c

+1 −1
Original line number Original line Diff line number Diff line
@@ -718,8 +718,8 @@ static void attach_default_qdiscs(struct net_device *dev) 
	} else {

	} else {

		qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT);

		qdisc = qdisc_create_dflt(txq, &mq_qdisc_ops, TC_H_ROOT);

		if (qdisc) {

		if (qdisc) {

			qdisc->ops->attach(qdisc);

			dev->qdisc = qdisc;

			dev->qdisc = qdisc;

			qdisc->ops->attach(qdisc);

		}

		}

	}

	}

}

}