From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754432Ab0ICTMu (ORCPT ); Fri, 3 Sep 2010 15:12:50 -0400 Received: from mail-bw0-f46.google.com ([209.85.214.46]:51571 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752372Ab0ICTMs convert rfc822-to-8bit (ORCPT ); Fri, 3 Sep 2010 15:12:48 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:reply-to:to:subject:date:user-agent:cc:references:in-reply-to :mime-version:content-type:content-transfer-encoding:message-id; b=I9bBx9ExTlPqlwQrJmW4Lcqh4mGBSnAiUpG0aLPVUJunPlhep33qMwxm3/vc4vTJNL rr2WvsYwgb+84iRnVmS18rnPSU5XB3nCKY9d10KcVx0paPqbu7weczYCyRKP+YFmP3rT gu5uHcRM9TKIYt3bepuPlu4Wq7b2TsQf1+A7w= From: Maciej Rutecki Reply-To: maciej.rutecki@gmail.com To: tim.gardner@canonical.com Subject: Re: nfsd deadlock, 2.6.36-rc3 Date: Fri, 3 Sep 2010 21:12:43 +0200 User-Agent: KMail/1.13.5 (Linux/2.6.36-rc3; KDE/4.4.5; i686; ; ) Cc: linux-nfs@vger.kernel.org, "linux-kernel@vger.kernel.org" , neilb@suse.de, bfields@fieldses.org, Trond.Myklebust@netapp.com References: <4C7E73CB.7030603@canonical.com> In-Reply-To: <4C7E73CB.7030603@canonical.com> MIME-Version: 1.0 Content-Type: Text/Plain; charset="utf-8" Content-Transfer-Encoding: 8BIT Message-Id: <201009032112.43524.maciej.rutecki@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On środa, 1 września 2010 o 17:39:55 Tim Gardner wrote: > I've been pursuing a simple reproducer for an NFS lockup that shows up > under stress. There is a bunch of info (some of it extraneous) in > http://bugs.launchpad.net/bugs/561210. I can reproduce it by writing > loop mounted NFS exports: > > /etc/fstab: 127.0.0.1:/srv /mnt/srv nfs rw 0 2 > /etc/exports: /srv 127.0.0.1(rw,insecure,no_subtree_check) > > See the attached scripts test_master.sh and test_client.sh. I simply > repeat './test_master.sh wait' until nfsd locks up, typically within 1-3 > cycles, e.g., > > cd /mnt/srv > while true; do ./test_master.sh wait; done > > Note that this test will run indefinitely if invoked from /srv, e.g., > > cd /srv > while true; do ./test_master.sh wait; done > > This issue, or something like it, appears to exist as far back as I've > tested (Ubuntu Lucid 2.6.32.21). For now I'm assuming that, since the > symptoms are similar, any lockup bug found in -rc3 is the likely culprit. > > See attached dmesg and config. Debug options of interest that I've > enabled are CONFIG_DEBUG_SLAB, CONFIG_DEBUG_SLAB_LEAK, > CONFIG_DEBUG_SPINLOCK, CONFIG_DEBUG_MUTEXES. > > dmesg.txt contains the initial 'INFO: task nfsd:1263 blocked for more > than 120 seconds.' complaints as well as information dumped from > > echo d | sudo tee /proc/sysrq-trigger > echo w | sudo tee /proc/sysrq-trigger > > Anything else I can provide? > > rtg I created a Bugzilla entry at https://bugzilla.kernel.org/show_bug.cgi?id=17762 for your bug report, please add your address to the CC list in there, thanks! -- Maciej Rutecki http://www.maciek.unixy.pl