From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Dumazet Subject: Re: Fwd: TCP fragmentation broken in 3.6-rc ? Date: Mon, 20 Aug 2012 17:14:30 +0200 Message-ID: <1345475670.5158.322.camel@edumazet-glaptop> References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: Sylvain Munaut Return-path: Received: from mail-bk0-f46.google.com ([209.85.214.46]:62247 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756671Ab2HTPOf (ORCPT ); Mon, 20 Aug 2012 11:14:35 -0400 Received: by bkwj10 with SMTP id j10so1892229bkw.19 for ; Mon, 20 Aug 2012 08:14:34 -0700 (PDT) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Mon, 2012-08-20 at 16:56 +0200, Sylvain Munaut wrote: > Hi, > > It seems somehow something was broken in 3.6-rc. > I'm not sure exactly what though. The symptoms are: > > - TCP connection get "stuck" with data in send queue when doing > "large" transfers ( like typing 'ps ax' on a ssh connection ) > - Only happens on path where the PMTU is lower than the MTU of the interface > - Is not present right after boot, it only appears 10-20min after > boot or so. (and that's inside the _same_ TCP connection, it works > fine at first and then in the same ssh session, it'll get stuck) > - Definitely seems related to fragments somehow since I see a router > sending ICMP message saying fragmentation is needed. > - Exact same setup works fine with kernel 3.5.1 > > Cheers, Could you make sure its not a pfmemalloc problem, by applying following patch : https://lkml.org/lkml/2012/8/20/182 Thanks