From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:53678 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753538AbdHKQVR (ORCPT ); Fri, 11 Aug 2017 12:21:17 -0400 Subject: Patch "tcp: avoid setting cwnd to invalid ssthresh after cwnd reduction states" has been added to the 4.9-stable tree To: ycheng@google.com, davem@davemloft.net, edumazet@google.com, gregkh@linuxfoundation.org, ncardwell@google.com Cc: , From: Date: Fri, 11 Aug 2017 09:21:12 -0700 Message-ID: <1502468472208221@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled tcp: avoid setting cwnd to invalid ssthresh after cwnd reduction states to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: tcp-avoid-setting-cwnd-to-invalid-ssthresh-after-cwnd-reduction-states.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From foo@baz Fri Aug 11 09:10:20 PDT 2017 From: Yuchung Cheng Date: Tue, 1 Aug 2017 13:22:32 -0700 Subject: tcp: avoid setting cwnd to invalid ssthresh after cwnd reduction states From: Yuchung Cheng [ Upstream commit ed254971edea92c3ac5c67c6a05247a92aa6075e ] If the sender switches the congestion control during ECN-triggered cwnd-reduction state (CA_CWR), upon exiting recovery cwnd is set to the ssthresh value calculated by the previous congestion control. If the previous congestion control is BBR that always keep ssthresh to TCP_INIFINITE_SSTHRESH, cwnd ends up being infinite. The safe step is to avoid assigning invalid ssthresh value when recovery ends. Signed-off-by: Yuchung Cheng Signed-off-by: Neal Cardwell Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/ipv4/tcp_input.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -2560,8 +2560,8 @@ static inline void tcp_end_cwnd_reductio return; /* Reset cwnd to ssthresh in CWR or Recovery (unless it's undone) */ - if (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR || - (tp->undo_marker && tp->snd_ssthresh < TCP_INFINITE_SSTHRESH)) { + if (tp->snd_ssthresh < TCP_INFINITE_SSTHRESH && + (inet_csk(sk)->icsk_ca_state == TCP_CA_CWR || tp->undo_marker)) { tp->snd_cwnd = tp->snd_ssthresh; tp->snd_cwnd_stamp = tcp_time_stamp; } Patches currently in stable-queue which might be from ycheng@google.com are queue-4.9/tcp-avoid-setting-cwnd-to-invalid-ssthresh-after-cwnd-reduction-states.patch queue-4.9/tcp-fastopen-tcp_connect-must-refresh-the-route.patch queue-4.9/net-fix-keepalive-code-vs-tcp_fastopen_connect.patch