From e1f52208bb968291f7d9142eff60b62984b4a511 Mon Sep 17 00:00:00 2001 From: YOSHIFUJI Hideaki Date: Tue, 11 Sep 2007 11:31:43 +0200 Subject: [PATCH] [IPv6]: Fix NULL pointer dereference in ip6_flush_pending_frames Some of skbs in sk->write_queue do not have skb->dst because we do not fill skb->dst when we allocate new skb in append_data(). BTW, I think we may not need to (or we should not) increment some stats when using corking; if 100 sendmsg() (with MSG_MORE) result in 2 packets, how many should we increment? If 100, we should set skb->dst for every queued skbs. If 1 (or 2 (*)), we increment the stats for the first queued skb and we should just skip incrementing OutDiscards for the rest of queued skbs, adn we should also impelement this semantics in other places; e.g., we should increment other stats just once, not 100 times. *: depends on the place we are discarding the datagram. I guess should just increment by 1 (or 2). Signed-off-by: YOSHIFUJI Hideaki Signed-off-by: David S. Miller --- net/ipv6/ip6_output.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 5dead399fe64..26de3c0ea31e 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1427,8 +1427,9 @@ void ip6_flush_pending_frames(struct sock *sk) struct sk_buff *skb; while ((skb = __skb_dequeue_tail(&sk->sk_write_queue)) != NULL) { - IP6_INC_STATS(ip6_dst_idev(skb->dst), - IPSTATS_MIB_OUTDISCARDS); + if (skb->dst) + IP6_INC_STATS(ip6_dst_idev(skb->dst), + IPSTATS_MIB_OUTDISCARDS); kfree_skb(skb); } -- 2.20.1