From: Eric Sesterhenn Subject: Re: BUG_ON at mballoc.c:3752 Date: Mon, 4 Feb 2008 09:29:36 +0100 Message-ID: <20080204082936.GB5284@alice> References: <20080131140137.GA20780@alice> <20080131154207.GA22201@alice> <20080204060055.GC7494@skywalker> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: linux-ext4@vger.kernel.org To: "Aneesh Kumar K.V" Return-path: Received: from mail.gmx.net ([213.165.64.20]:56133 "HELO mail.gmx.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753757AbYBDI3j (ORCPT ); Mon, 4 Feb 2008 03:29:39 -0500 Content-Disposition: inline In-Reply-To: <20080204060055.GC7494@skywalker> Sender: linux-ext4-owner@vger.kernel.org List-ID: * Aneesh Kumar K.V (aneesh.kumar@linux.vnet.ibm.com) wrote: > On Thu, Jan 31, 2008 at 04:42:07PM +0100, Eric Sesterhenn wrote: > > * Eric Sesterhenn (snakebyte@gmx.de) wrote: > > > hi, > > > > > > while running a modified version of fsfuzzer i triggered the BUG() in > > > ext4_mb_release_inode_pa(). Sadly I am not able to reproduce this using > > > the generated image, but running the fuzzer will usually trigger this in > > > less than 40 attempts. Increasing the JBD2 Debug level didnt give more > > > information. The kernel is current git with > > > ext4-fix-null-pointer-deref-in-journal_wait_on_commit_record.patch > > > applied. > > > > I am now able to reproduce this using this image: > > http://www.cccmz.de/~snakebyte/ext4.24.img.bz2 > > > > the following commands will trigger the oops for me > > > > mount cfs/ext4.24.img /media/test -t ext4dev -o extents -o loop > > mkdir /media/test/stress > > chown snakebyte:snakebyte /media/test/stress && sudo -u snakebyte fstest -n 10 -l 10 -f 5 -s 40000 -p /media/test/stress/ > > > > The file system is corrupted. The BUG_ON indicate that the free spcae > marked in the prealloc space and found by looking at the bitmap are not > same. Do you have a set of steps that i can follow to reproduce this ? just compile the mangle.c and run the modified fuzzer for a while (link below) or use the steps above > on a clean file system ? had no luck on a clean fs with this > Where do i find the fsfuzzer that you are using ? http://www.cccmz.de/~snakebyte/fsfuzzer-0.6-lmh-eric.tar.bz2 http://www.cccmz.de/~snakebyte/fsfuzz.diff needs user/group nobody:nobody and stuff like fstest, fsx, iozone, fsstress The changes i made are basically changing the fuzzing ratio, adding udf, hfsplus and ext4, reducing the number of runs to 100 (not unlimited), saving a backup of the image before mounting and running the tests, and mounting ext3 with -o debug Greetings, Eric