This is a note to let you know that I've just added the patch titled
tcp: frto should not set snd_cwnd to 0
to the 3.4-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-frto-should-not-set-snd_cwnd-to-0.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 684377af90fbb1ed24f85359063a3d8c9fed4611 Mon Sep 17 00:00:00 2001
From: Eric Dumazet <[email protected]>
Date: Sun, 3 Feb 2013 09:13:05 +0000
Subject: tcp: frto should not set snd_cwnd to 0
From: Eric Dumazet <[email protected]>
[ Upstream commit 2e5f421211ff76c17130b4597bc06df4eeead24f ]
Commit 9dc274151a548 (tcp: fix ABC in tcp_slow_start())
uncovered a bug in FRTO code :
tcp_process_frto() is setting snd_cwnd to 0 if the number
of in flight packets is 0.
As Neal pointed out, if no packet is in flight we lost our
chance to disambiguate whether a loss timeout was spurious.
We should assume it was a proper loss.
Reported-by: Pasi Kärkkäinen <[email protected]>
Signed-off-by: Neal Cardwell <[email protected]>
Signed-off-by: Eric Dumazet <[email protected]>
Cc: Ilpo Järvinen <[email protected]>
Cc: Yuchung Cheng <[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
@@ -3619,7 +3619,8 @@ static int tcp_process_frto(struct sock
((tp->frto_counter >= 2) && (flag & FLAG_RETRANS_DATA_ACKED)))
tp->undo_marker = 0;
- if (!before(tp->snd_una, tp->frto_highmark)) {
+ if (!before(tp->snd_una, tp->frto_highmark) ||
+ !tcp_packets_in_flight(tp)) {
tcp_enter_frto_loss(sk, (tp->frto_counter == 1 ? 2 : 3), flag);
return 1;
}
Patches currently in stable-queue which might be from [email protected] are
queue-3.4/tcp-frto-should-not-set-snd_cwnd-to-0.patch
queue-3.4/tcp-fix-for-zero-packets_in_flight-was-too-broad.patch
queue-3.4/net-prevent-setting-ttl-0-via-ip_ttl.patch
queue-3.4/netxen-fix-off-by-one-bug-in-netxen_release_tx_buffer.patch
queue-3.4/net-loopback-fix-a-dst-refcounting-issue.patch
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