From ca2c1418efe9f7fe37aa1f355efdf4eb293673ce Mon Sep 17 00:00:00 2001 From: Paolo Abeni Date: Wed, 6 Sep 2017 14:44:36 +0200 Subject: udp: drop head states only when all skb references are gone After commit 0ddf3fb2c43d ("udp: preserve skb->dst if required for IP options processing") we clear the skb head state as soon as the skb carrying them is first processed. Since the same skb can be processed several times when MSG_PEEK is used, we can end up lacking the required head states, and eventually oopsing. Fix this clearing the skb head state only when processing the last skb reference. Reported-by: Eric Dumazet Fixes: 0ddf3fb2c43d ("udp: preserve skb->dst if required for IP options processing") Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller --- net/ipv4/udp.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'net/ipv4') diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c index db1c9e78c83c..ef29df8648e4 100644 --- a/net/ipv4/udp.c +++ b/net/ipv4/udp.c @@ -1397,12 +1397,15 @@ void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len) unlock_sock_fast(sk, slow); } + if (!skb_unref(skb)) + return; + /* In the more common cases we cleared the head states previously, * see __udp_queue_rcv_skb(). */ if (unlikely(udp_skb_has_head_state(skb))) skb_release_head_state(skb); - consume_stateless_skb(skb); + __consume_stateless_skb(skb); } EXPORT_SYMBOL_GPL(skb_consume_udp); -- cgit v1.2.3