Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758219Ab1DMKZL (ORCPT ); Wed, 13 Apr 2011 06:25:11 -0400 Received: from lon1-post-3.mail.demon.net ([195.173.77.150]:45150 "EHLO lon1-post-3.mail.demon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757087Ab1DMKZI (ORCPT ); Wed, 13 Apr 2011 06:25:08 -0400 Subject: Re: Commit 7eaceaccab5f40 causing boot hang. From: Richard Kennedy To: Jens Axboe Cc: Tejun Heo , Rob Landley , Pete Clements , linux-kernel , "linux-ide@vger.kernel.org" In-Reply-To: <1301924863.8526.9.camel@castor.rsk> References: <201103291551.p2TFpDqZ001692@clem.clem-digital.net> <4D92C874.7040104@parallels.com> <4D931634.5030807@fusionio.com> <4D933584.5050005@parallels.com> <4D94432D.5080601@fusionio.com> <4D944544.9040705@parallels.com> <4D945247.4080404@fusionio.com> <4D945976.8000401@fusionio.com> <20110331121100.GD3385@htj.dyndns.org> <4D9474AA.4070402@fusionio.com> <4D947D12.6070505@rsk.demon.co.uk> <4D947F29.5050203@fusionio.com> <1301577831.1984.2.camel@castor.rsk> <4D9482BA.8080807@fusionio.com> <1301582977.1984.7.camel@castor.rsk> <1301924863.8526.9.camel@castor.rsk> Content-Type: text/plain; charset="UTF-8" Date: Wed, 13 Apr 2011 11:25:00 +0100 Message-ID: <1302690300.1993.7.camel@castor.rsk> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 (2.32.2-1.fc14) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3124 Lines: 98 On Mon, 2011-04-04 at 14:47 +0100, Richard Kennedy wrote: > On Thu, 2011-03-31 at 15:49 +0100, Richard Kennedy wrote: > > On Thu, 2011-03-31 at 15:33 +0200, Jens Axboe wrote: > >[...] > > > >>> Hi Jens, > > > >>> > > > >>> I'm seeing a problem with fio never completing when writing to 2 disks > > > >>> simultaneously. In my test case I'm writing 2Gb to both a LVM volume & a > > > >>> pata drive on x86_64 on a AMD X2. Could this be a related issue? > > > >>> > > > >>> I'm not getting anything reported in the log, lockup detection doesn't > > > >>> report anything either. The write seems to have finished (the disk light > > > >>> activity has stopped) and the cpu cores are both below 10% usage, but > > > >>> fio never returns. The test does complete some times, but it seems to be > > > >>> one 1 in 4. > > > >> > > > >> So when you say PATA, it's /dev/hdaX something as well? > > > >> > > > >>> I'm going to try tracing it and see if I can spot where it's stuck. > > > >> > > > >> Thanks, that would be nice. > > > >> > > > > The second drive is /dev/sdb1 mounted on /opt, both file systems are > > > > ext4. > > > > > > So probably not related. What does the fio job look like? > > > > > fio job file -- > > [global] > > pre_read=1 > > ioengine=mmap > > > > [f1] > > size=2g > > rw=write > > directory=/home/tests > > > > [f2] > > size=2g > > rw=write > > directory=/opt/tests > > > > Fio gets run from a script that also collects stats but it's been > > running without any problems up until 2.6.39-rc1. > > > Hi Jens > I've upgrade to the latest fio version in the git repo 1.51 and I'm > still seeing this problem. > > Fio gets stuck after it writes the 100% complete message and strace on > the processes shows this. > > the controlling fio process :- > ... > [pid 8439] wait4(8442, 0x7fff848203ac, WNOHANG, NULL) = 0 > [pid 8439] nanosleep({0, 10000000}, NULL) = 0 > [pid 8439] wait4(8441, 0x7fff848203ac, WNOHANG, NULL) = 0 > [pid 8439] wait4(8442, 0x7fff848203ac, WNOHANG, NULL) = 0 > [pid 8439] nanosleep({0, 10000000} > > & the 2 workers are both stopped here, strace shows only the one line > for each process. > > Process 8441 attached - interrupt to quit > futex(0x7f9db76a802c, FUTEX_WAIT_PRIVATE, 2, NULL > > > Process 8442 attached - interrupt to quit > futex(0x7f9db76a802c, FUTEX_WAIT_PRIVATE, 2, NULL > > How do I find out which futex it's waiting for? > Any ideas where I should look next ? > > I can run the same test successfully on 2.6.38 so is it worth trying to > bisect this ? > > thanks > Richard > My problem has gone away in v2.6.39-rc3. I've just finished bisecting it down to 6de9843dab3f, & that got reverted in rc3, so no problem ;) (The data corruption caused by that faulty commit was zeroing out the shared mutexs in fio & the worker threads were getting stuck on the writeout_mutex.) regards Richard -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/