This is a note to let you know that I've just added the patch titled

    tcp: only take RTT from timestamps if new data is acked

to the 3.12-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-only-take-rtt-from-timestamps-if-new-data-is-acked.patch
and it can be found in the queue-3.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From 49627d9ffd019bffa9613a2dcfb34f3e85adcf6c Mon Sep 17 00:00:00 2001
From: Yuchung Cheng <[email protected]>
Date: Thu, 24 Oct 2013 08:55:25 -0700
Subject: tcp: only take RTT from timestamps if new data is acked

From: Yuchung Cheng <[email protected]>

[ Upstream commit 2909d874f34eae157aecab0af27c6dc4a1751f8f ]

Patch ed08495c3 "tcp: use RTT from SACK for RTO" has a bug that
it does not check if the ACK acknowledge new data before taking
the RTT sample from TCP timestamps. This patch adds the check
back as required by the RFC.

Signed-off-by: Yuchung Cheng <[email protected]>
Acked-by: Neal Cardwell <[email protected]>
Acked-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 net/ipv4/tcp_input.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2856,7 +2856,8 @@ static inline bool tcp_ack_update_rtt(st
         * left edge of the send window.
         * See draft-ietf-tcplw-high-performance-00, section 3.3.
         */
-       if (seq_rtt < 0 && tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr)
+       if (seq_rtt < 0 && tp->rx_opt.saw_tstamp && tp->rx_opt.rcv_tsecr &&
+           flag & FLAG_ACKED)
                seq_rtt = tcp_time_stamp - tp->rx_opt.rcv_tsecr;
 
        if (seq_rtt < 0)


Patches currently in stable-queue which might be from [email protected] are

queue-3.12/tcp-only-take-rtt-from-timestamps-if-new-data-is-acked.patch
queue-3.12/tcp-fix-synack-rtt-estimation-in-fast-open.patch
queue-3.12/tcp-do-not-rearm-rto-when-future-data-are-sacked.patch
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