Commit 92f91706 authored Apr 04, 2017 by WANG Cong Committed by David S. Miller Apr 06, 2017

net_sched: check noop_qdisc before qdisc_hash_add()



Dmitry reported a crash when injecting faults in
attach_one_default_qdisc() and dev->qdisc is still
a noop_disc, the check before qdisc_hash_add() fails
to catch it because it tests NULL. We should test
against noop_qdisc since it is the default qdisc
at this point.

Fixes: 59cc1f61 ("net: sched: convert qdisc linked list to hashtable")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Cc: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent a8801799

net/sched/sch_generic.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -794,7 +794,7 @@ static void attach_default_qdiscs(struct net_device *dev)
		}
		}
		#ifdef CONFIG_NET_SCHED
		if (dev->qdisc)
		if (dev->qdisc != &noop_qdisc)
		qdisc_hash_add(dev->qdisc);
		#endif
		}

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