From 07f29bc5bbae4e53e982ab956fed7207990a7786 Mon Sep 17 00:00:00 2001 From: Damian Lukowski Date: Mon, 7 Dec 2009 06:06:15 +0000 Subject: [PATCH] tcp: Stalling connections: Fix timeout calculation routine MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit This patch fixes a problem in the TCP connection timeout calculation. Currently, timeout decisions are made on the basis of the current tcp_time_stamp and retrans_stamp, which is usually set at the first retransmission. However, if the retransmission fails in tcp_retransmit_skb(), retrans_stamp is not updated and remains zero. This leads to wrong decisions in retransmits_timed_out() if tcp_time_stamp is larger than the specified timeout, which is very likely. In this case, the TCP connection dies after the first attempted (and unsuccessful) retransmission. With this patch, tcp_skb_cb->when is used instead, when retrans_stamp is not available. This bug has been introduced together with retransmits_timed_out() in 2.6.32, as the number of retransmissions has been used for timeout decisions before. The corresponding commit was 6fa12c85031485dff38ce550c24f10da23b0adaa (Revert Backoff [v3]: Calculate TCP's connection close threshold as a time value.). Thanks to Ilpo Järvinen for code suggestions and Frederic Leroy for testing. Reported-by: Frederic Leroy Signed-off-by: Damian Lukowski Acked-by: Ilpo Järvinen Signed-off-by: David S. Miller --- Reading git-format-patch failed