From 1df94c3c5dadbce3df6cc0e989d8c85d43a903d6 Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Mon, 18 Dec 2017 14:34:26 -0800 Subject: [PATCH] net_sched: properly check for empty skb array on error path 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 Cc: John Fastabend Signed-off-by: Cong Wang Acked-by: John Fastabend Signed-off-by: David S. Miller --- net/sched/sch_generic.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 981c08fe810b..876fab2604b8 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -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. -- 2.11.0