Guaranteed kernel panic with ZFS + nullfs

[Luke Marsden]

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)
> > 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

Thank you!

-- 
Best Regards,
Luke Marsden
CTO, Hybrid Logic Ltd.

Web: http://www.hybrid-cluster.com/
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