From: Eric Dumazet <edumazet@google.com>
Date: Mon, 17 Sep 2012 12:51:39 +0000 (+0000)
Subject: tcp: fix regression in urgent data handling
X-Git-Tag: v3.5.7~108
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3ccda9bc19a76edeea574127be4478648426f3d2;p=thirdparty%2Fkernel%2Fstable.git

tcp: fix regression in urgent data handling

[ Upstream commit 1d57f19539c074105791da6384a8ad674bba8037 ]

Stephan Springl found that commit 1402d366019fed "tcp: introduce
tcp_try_coalesce" introduced a regression for rlogin

It turns out problem comes from TCP urgent data handling and
a change in behavior in input path.

rlogin sends two one-byte packets with URG ptr set, and when next data
frame is coalesced, we lack sk_data_ready() calls to wakeup consumer.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Stephan Springl <springl-k@lar.bfw.de>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 262316b75bcfe..ab30c963930e1 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -4818,7 +4818,7 @@ queue_and_out:
 
 		if (eaten > 0)
 			kfree_skb_partial(skb, fragstolen);
-		else if (!sock_flag(sk, SOCK_DEAD))
+		if (!sock_flag(sk, SOCK_DEAD))
 			sk->sk_data_ready(sk, 0);
 		return;
 	}
@@ -5680,8 +5680,7 @@ no_ack:
 #endif
 			if (eaten)
 				kfree_skb_partial(skb, fragstolen);
-			else
-				sk->sk_data_ready(sk, 0);
+			sk->sk_data_ready(sk, 0);
 			return 0;
 		}
 	}