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net_sched: properly check for empty skb array on error path

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First, the check of &q->ring.queue against NULL is wrong, it
is always false. We should check the value rather than the address.

Secondly, we need the same check in pfifo_fast_reset() too,
as both ->reset() and ->destroy() are called in qdisc_destroy().

Fixes: c5ad119fb6c0 ("net: sched: pfifo_fast use skb_array")
Reported-by: syzbot <syzkaller@googlegroups.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Cong Wang 2017-12-18 14:34:26 -08:00 committed by David S. Miller
parent 4eb50ceb5c
commit 1df94c3c5d
1 changed files with 7 additions and 1 deletions
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8
net/sched/sch_generic.c
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@ -659,6 +659,12 @@ static void pfifo_fast_reset(struct Qdisc *qdisc)
struct skb_array *q = band2list(priv, band);
struct sk_buff *skb;
/* NULL ring is possible if destroy path is due to a failed
* skb_array_init() in pfifo_fast_init() case.
*/
if (!q->ring.queue)
continue;
while ((skb = skb_array_consume_bh(q)) != NULL)
kfree_skb(skb);
}
@ -719,7 +725,7 @@ static void pfifo_fast_destroy(struct Qdisc *sch)
/* NULL ring is possible if destroy path is due to a failed
* skb_array_init() in pfifo_fast_init() case.
*/
if (!&q->ring.queue)
if (!q->ring.queue)
continue;
/* Destroy ring but no need to kfree_skb because a call to
* pfifo_fast_reset() has already done that work.