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authorEric Dumazet <edumazet@google.com>2012-05-23 17:51:37 +0000
committerDavid S. Miller <davem@davemloft.net>2012-05-24 00:28:21 -0400
commit1ca7ee30630e1022dbcf1b51be20580815ffab73 (patch)
tree5aab9c5bd4e31617afce262672c833db26381a23 /net
parente49cc0da7283088c5e03d475ffe2fdcb24a6d5b1 (diff)
downloadlinux-1ca7ee30630e1022dbcf1b51be20580815ffab73.tar.gz
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> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp_input.c5
1 files changed, 5 insertions, 0 deletions
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index cfa2aa12834..b224eb8bce8 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;