]> git.baikalelectronics.ru Git - kernel.git/commit
tcp: Do not apply TSO segment limit to non-TSO packets
authorHerbert Xu <herbert@gondor.apana.org.au>
Wed, 31 Dec 2014 13:39:23 +0000 (00:39 +1100)
committerDavid S. Miller <davem@davemloft.net>
Fri, 2 Jan 2015 21:13:20 +0000 (16:13 -0500)
commitc8dfd2a61600c6aa930debb0f1c5f8d5181b29c5
tree530f87ef25fccc495166de5a2e520e4e94871f9a
parent9e9732aeb6e7a40b0a3700d353af6fa07e0eb5c0
tcp: Do not apply TSO segment limit to non-TSO packets

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: b3242268e43 ("tcp: Apply device TSO segment limit earlier")
Reported-by: Thomas Jarosch <thomas.jarosch@intra2net.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Cheers,
Signed-off-by: David S. Miller <davem@davemloft.net>
net/ipv4/tcp_output.c