From: Sami Liedes Subject: Re: [Bugme-new] [Bug 11266] New: unable to handle kernel paging request in ext2_free_blocks Date: Tue, 19 Aug 2008 13:51:12 +0300 Message-ID: <20080819105111.GK8997@lh.kyla.fi> References: <0K5800031SEDU2@smtp02.hut-mail> <20080807200717.GB26307@lh.kyla.fi> <20080807202840.GC26307@lh.kyla.fi> <20080818145841.GC10621@atrey.karlin.mff.cuni.cz> <20080818165131.GC6491@skywalker> <20080819032410.GE3392@webber.adilger.int> <20080819091339.GE14799@duck.suse.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Andreas Dilger , "Aneesh Kumar K.V" , Andrew Morton , bugme-daemon@bugzilla.kernel.org, linux-ext4@vger.kernel.org To: Jan Kara Return-path: Received: from smtp-4.hut.fi ([130.233.228.94]:49579 "EHLO smtp-4.hut.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752126AbYHSLDP (ORCPT ); Tue, 19 Aug 2008 07:03:15 -0400 Content-Disposition: inline In-Reply-To: <20080819091339.GE14799@duck.suse.cz> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Tue, Aug 19, 2008 at 11:13:39AM +0200, Jan Kara wrote: > > Isn't equivalent checking done in ext2_check_descriptors()? It would make > > sense to abstract out the "check one group and return error" code and use > > it in both places. > Actually yes, it is. Good point. Sami, is it the case that you have > mounted the filesystem, then intentionally corrupted it and after that > the kernel oopsed (as opposed to first corrupting the filesystem image and > mounting it after that)? That would explain how corrupted values could get > to read_block_bitmap() even though ext2_check_descriptors() checked them. No, that's not what I do. I corrupt the fs before mounting it, then mount it, perform normal filesystem operations on it and unmount it. Here's the most current script I use (zzuf is the fuzzer): ------------------------------------------------------------ #!/bin/sh if [ "`hostname`" != "fstest" ]; then echo "This is a dangerous script." echo "Set your hostname to \`fstest\' if you want to use it." exit 1 fi umount /dev/hdb umount /dev/hdc /etc/init.d/sysklogd stop /etc/init.d/klogd stop /etc/init.d/cron stop mount /dev/hda / -t ext3 -o remount,ro || exit 1 #ulimit -t 20 for ((s=$1; s<1000000000; s++)); do umount /mnt echo '***** zzuffing *****' seed $s zzuf -r 0:0.03 -s $s /dev/hdb || exit mount /dev/hdb /mnt -t ext2 -o errors=continue || continue cd /mnt || continue timeout 30 cp -r doc doc2 >&/dev/null timeout 30 find -xdev >&/dev/null timeout 30 find -xdev -print0 2>/dev/null |xargs -0 touch -- 2>/dev/null timeout 30 mkdir tmp >&/dev/null timeout 30 echo whoah >tmp/filu 2>/dev/null timeout 30 rm -rf /mnt/* >&/dev/null cd / done ------------------------------------------------------------ Sami