From: Dave Kleikamp Subject: Re: BUG_ON at mballoc.c:3752 Date: Wed, 06 Feb 2008 15:59:48 -0600 Message-ID: <1202335188.6886.15.camel@norville.austin.ibm.com> References: <20080131140137.GA20780@alice> <20080131154207.GA22201@alice> <20080204060055.GC7494@skywalker> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Cc: Eric Sesterhenn , linux-ext4@vger.kernel.org To: "Aneesh Kumar K.V" Return-path: Received: from e6.ny.us.ibm.com ([32.97.182.146]:44024 "EHLO e6.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753566AbYBFV7u (ORCPT ); Wed, 6 Feb 2008 16:59:50 -0500 Received: from d01relay02.pok.ibm.com (d01relay02.pok.ibm.com [9.56.227.234]) by e6.ny.us.ibm.com (8.13.8/8.13.8) with ESMTP id m16M1ida013342 for ; Wed, 6 Feb 2008 17:01:44 -0500 Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay02.pok.ibm.com (8.13.8/8.13.8/NCO v8.7) with ESMTP id m16Lxo6n228842 for ; Wed, 6 Feb 2008 16:59:50 -0500 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id m16Lxnc5021759 for ; Wed, 6 Feb 2008 16:59:49 -0500 In-Reply-To: <20080204060055.GC7494@skywalker> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Mon, 2008-02-04 at 11:30 +0530, Aneesh Kumar K.V 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. That's what fsfuzzer does. > The BUG_ON indicate that the free spcae > marked in the prealloc space and found by looking at the bitmap are not > same. File systems should not call BUG() due to a corrupt file system. Instead the code should fail the operation, possibly marking the file system read-only (or panicking) depending on the errors= mount option. -- David Kleikamp IBM Linux Technology Center