[dm-devel] logfs: kernel NULL dereference

Jörn Engel joern at logfs.org
Thu Sep 15 14:52:04 UTC 2011


On Thu, 15 September 2011 16:27:52 +0200, Milan Broz wrote:
> On 09/14/2011 08:34 PM, Jörn Engel wrote:
> > Forwarded to dm-devel.  Problem is a NULL pointer dereference in
> > kcryptd_io_read, which is triggered when mounting logfs.  If someone
> > with device mapper knowledge could have a look, that would be useful.
> > 
> > On Wed, 14 September 2011 20:24:25 +0200, Jörn Engel wrote:
> >>
> >> Ok, I can reliably reproduce the problem with the following, based on
> >> your description:
> >>
> >> truncate -s 0 foo
> >> truncate -s 1G foo
> >> losetup -v -f foo
> >> cryptsetup luksFormat /dev/loop0
> >> cryptsetup luksOpen /dev/loop0 foo
> >> pvcreate /dev/mapper/foo
> >> vgcreate our_volume /dev/mapper/foo
> >> lvcreate -L 128M -n logfstest our_volume
> >> yes yes | mklogfs /dev/mapper/our_volume-logfstest
> >> mount /dev/mapper/our_volume-logfstest /mnt/
> 
> Which kernel version are you using?

Latest git - well, close to latest, given the current kernel.org trouble.

> >> It is a bit annoying that cryptsetup cannot easily be scripted.
> 
> It can be easily scripted. (In quiet mode it will not ask for YES response, add -q,
> or just do "echo -n $PASSWORD | cryptsetup luksFormat ...")

Ok, I'll use that in the future.  Thanks.

Jörn

-- 
More computing sins are committed in the name of efficiency (without
necessarily achieving it) than for any other single reason - including
blind stupidity.
-- W. A. Wulf




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