Message ID | 1337831497.3361.3888.camel@edumazet-glaptop |
---|---|
State | Accepted, archived |
Delegated to: | David Miller |
Headers | show |
From: Eric Dumazet <eric.dumazet@gmail.com> Date: Thu, 24 May 2012 05:51:37 +0200 > [PATCH] tcp: take care of overlaps in tcp_try_coalesce() > > Sergio Correia reported following warning : > > WARNING: at net/ipv4/tcp.c:1301 tcp_cleanup_rbuf+0x4f/0x110() > > WARN(skb && !before(tp->copied_seq, TCP_SKB_CB(skb)->end_seq), > "cleanup rbuf bug: copied %X seq %X rcvnxt %X\n", > tp->copied_seq, TCP_SKB_CB(skb)->end_seq, tp->rcv_nxt); > > It appears TCP coalescing, and more specifically commit b081f85c297 > (net: implement tcp coalescing in tcp_queue_rcv()) should take care of > possible segment overlaps in receive queue. This was properly done in > the case of out_or_order_queue by the caller. > > For example, segment at tail of queue have sequence 1000-2000, and we > add a segment with sequence 1500-2500. > This can happen in case of retransmits. > > In this case, just don't do the coalescing. > > Reported-by: Sergio Correia <lists@uece.net> > Signed-off-by: Eric Dumazet <edumazet@google.com> > Tested-by: Sergio Correia <lists@uece.net> Applied, thanks. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index cfa2aa1..b224eb8 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -4555,6 +4555,11 @@ static bool tcp_try_coalesce(struct sock *sk, if (tcp_hdr(from)->fin) return false; + + /* Its possible this segment overlaps with prior segment in queue */ + if (TCP_SKB_CB(from)->seq != TCP_SKB_CB(to)->end_seq) + return false; + if (!skb_try_coalesce(to, from, fragstolen, &delta)) return false;