From mboxrd@z Thu Jan 1 00:00:00 1970 From: ebiederm@xmission.com (Eric W. Biederman) Subject: Re: Reported regression against commit a05d2ad Date: Tue, 21 Jun 2011 13:49:45 -0700 Message-ID: References: <20110621201528.GB2249@herton-IdeaPad-Y430> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: lamont@canonical.com, sconklin@canonical.com, tim.gardner@canonical.com, netdev@vger.kernel.org To: Herton Ronaldo Krzesinski Return-path: Received: from out01.mta.xmission.com ([166.70.13.231]:52133 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757558Ab1FUUtu (ORCPT ); Tue, 21 Jun 2011 16:49:50 -0400 In-Reply-To: <20110621201528.GB2249@herton-IdeaPad-Y430> (Herton Ronaldo Krzesinski's message of "Tue, 21 Jun 2011 17:15:29 -0300") Sender: netdev-owner@vger.kernel.org List-ID: Herton Ronaldo Krzesinski writes: > 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. The only thing commit a05d2ad will prevent is a non-sense use of a af_unix socket, and on recent enough kernels a NULL pointer deference. I respectfully suggest that the bug is elsewhere perhaps a broken user space application out there that needs to be fixed, or you have a kernel memory stomp that removing patch a05d2ad happens to shift the memory layout to be harmful in a different way. af_unix sockets have nothing to do with tcp and only happen to use the TCP_ESTABLISHED flag to indicated connected or non-connected sockets. Eric > I'm adding reporter to CC (Lamont), in case more details are necessary > etc.