Date: Thu, 17 Mar 2011 15:41:43 +0200 From: Andriy Gapon <avg@freebsd.org> To: luke@hybrid-logic.co.uk Cc: freebsd-fs@freebsd.org Subject: Re: Guaranteed kernel panic with ZFS + nullfs Message-ID: <4D820F97.5090201@freebsd.org> In-Reply-To: <1300365280.3837.129.camel@pow> References: <1300334881.3837.126.camel@pow> <20110317113744.GT78089@deviant.kiev.zoral.com.ua> <1300365280.3837.129.camel@pow>
next in thread | previous in thread | raw e-mail | index | archive | help
on 17/03/2011 14:34 Luke Marsden said the following: > On Thu, 2011-03-17 at 13:37 +0200, Kostik Belousov wrote: >> [Enormous Cc: list trimmed down] >> On Thu, Mar 17, 2011 at 12:08:01AM -0400, Luke Marsden wrote: >>> Hi all, >>> >>> The following script seems to cause a guaranteed kernel panic on 8.1-R, >>> 8.2-R and 8-STABLE as of today (2011-03-16), with both ZFS v14/15, and >>> v28 on 8.2-R with mm@ patches from 2011-03. I suspect it may also affect >>> 9-CURRENT but have not tested this yet. >>> >>> #!/usr/local/bin/bash >>> export POOL=hpool # change this to your pool name >>> sudo zfs destroy -r $POOL/foo >>> sudo zfs create $POOL/foo >>> sudo zfs set mountpoint=/foo $POOL/foo >>> sudo mount -t nullfs /foo /bar >>> sudo touch /foo/baz >>> ls /bar # should see baz >>> sudo zfs umount -f $POOL/foo # seems okay (ls: /bar: Bad file >>> descriptor) I believe that it's a bad idea to forcefully unmount a filesystem under a nullfs mount. Without -f the unmounting wouldn't succeed? >>> sudo zfs mount $POOL/foo # PANIC! >>> >>> Can anyone suggest a patch which fixes this? Preferably against >>> 8-STABLE :-) >> Please show the backtrace. >> > > Here you go: > > http://lukemarsden.net/zfs-panic-1.png > http://lukemarsden.net/zfs-panic-2.png IMO this is expected. I am not sure if this is ZFS specific or if it can happen with any kind of an underlying filesystem. Maybe Edward would be interested in fixing this behavior? :) -- Andriy Gapon
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?4D820F97.5090201>