From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tim Gardner Subject: Re: Reported regression against commit a05d2ad Date: Tue, 21 Jun 2011 14:38:50 -0600 Message-ID: <4E01015A.2030709@canonical.com> References: <20110621201528.GB2249@herton-IdeaPad-Y430> Reply-To: tim.gardner@canonical.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: "Eric W. Biederman" , lamont@canonical.com, sconklin@canonical.com, netdev@vger.kernel.org To: Herton Ronaldo Krzesinski Return-path: Received: from mail.tpi.com ([70.99.223.143]:4770 "EHLO mail.tpi.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757220Ab1FUUjM (ORCPT ); Tue, 21 Jun 2011 16:39:12 -0400 In-Reply-To: <20110621201528.GB2249@herton-IdeaPad-Y430> Sender: netdev-owner@vger.kernel.org List-ID: On 06/21/2011 02:15 PM, Herton Ronaldo Krzesinski wrote: > Hi, > > after update to one of the latest 2.6.32.x stable kernels for Ubuntu, we > got a regression report about timeout in tcp connections > (https://launchpad.net/bugs/791512). > > We tried help reporter with a bisect process, but it was taking some > time, so we reverted some suspect commits, until we isolated it to > commit "af_unix: Only allow recv on connected seqpacket sockets." > > With only commit a05d2ad reverted, testing results so far indicate the > issue doesn't happen. > > I'm unfamiliar with unix sockets code, so can't see at first why this > commit in particular is causing problems, for now I can only say may be > something at application level using unix sockets regressed with it (?). > I'm just reporting it right now, and we plan to revert it for that kernel > until more info is found about it. > > I'm adding reporter to CC (Lamont), in case more details are necessary > etc. > I believe we're also homing in on the same regression in 2.6.38.6 ('af_unix: Only allow recv on connected seqpacket sockets.'). The functional part of the patch is: + + if (sk->sk_state != TCP_ESTABLISHED) + return -ENOTCONN; + + return unix_dgram_recvmsg(iocb, sock, msg, size, flags); What happens with out of order receives? Would fragmentation have an impact? rtg -- Tim Gardner tim.gardner@canonical.com