This is a note to let you know that I've just added the patch titled
tcp: Do not apply TSO segment limit to non-TSO packets
to the 3.14-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-do-not-apply-tso-segment-limit-to-non-tso-packets.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From foo@baz Sat Jan 17 18:13:02 PST 2015
From: Herbert Xu <[email protected]>
Date: Thu, 1 Jan 2015 00:39:23 +1100
Subject: tcp: Do not apply TSO segment limit to non-TSO packets
From: Herbert Xu <[email protected]>
[ Upstream commit 843925f33fcc293d80acf2c5c8a78adf3344d49b ]
Thomas Jarosch reported IPsec TCP stalls when a PMTU event occurs.
In fact the problem was completely unrelated to IPsec. The bug is
also reproducible if you just disable TSO/GSO.
The problem is that when the MSS goes down, existing queued packet
on the TX queue that have not been transmitted yet all look like
TSO packets and get treated as such.
This then triggers a bug where tcp_mss_split_point tells us to
generate a zero-sized packet on the TX queue. Once that happens
we're screwed because the zero-sized packet can never be removed
by ACKs.
Fixes: 1485348d242 ("tcp: Apply device TSO segment limit earlier")
Reported-by: Thomas Jarosch <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>
Cheers,
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
net/ipv4/tcp_output.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -1894,7 +1894,7 @@ static bool tcp_write_xmit(struct sock *
if (unlikely(!tcp_snd_wnd_test(tp, skb, mss_now)))
break;
- if (tso_segs == 1) {
+ if (tso_segs == 1 || !sk->sk_gso_max_segs) {
if (unlikely(!tcp_nagle_test(tp, skb, mss_now,
(tcp_skb_is_last(sk, skb) ?
nonagle :
TCP_NAGLE_PUSH))))
@@ -1931,7 +1931,7 @@ static bool tcp_write_xmit(struct sock *
}
limit = mss_now;
- if (tso_segs > 1 && !tcp_urg_mode(tp))
+ if (tso_segs > 1 && sk->sk_gso_max_segs && !tcp_urg_mode(tp))
limit = tcp_mss_split_point(sk, skb, mss_now,
min_t(unsigned int,
cwnd_quota,
Patches currently in stable-queue which might be from
[email protected] are
queue-3.14/tcp-do-not-apply-tso-segment-limit-to-non-tso-packets.patch
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