Bug#586985: [grub-common] Regression: grub-probe fails

[Peter Fritzsche]

Package: grub-common
Version: 1.98-1
Severity: normal

I cannot update my system anymore as grub-probe stops the installation and 
deinstallation of memtest86+

Unpacking replacement memtest86+ ...
/usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?).
dpkg: warning: subprocess old post-removal script returned error exit status 1
dpkg - trying script from the new package instead ...
/usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?).
dpkg: error processing /var/cache/apt/archives/memtest86+_4.00-2.3_amd64.deb 
(--unpack):
 subprocess new post-removal script returned error exit status 1
/usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?).
dpkg: error while cleaning up:
 subprocess new post-removal script returned error exit status 1
Preparing to replace e2fslibs 1.41.12-1 (using 
.../e2fslibs_1.41.12-2_amd64.deb) ...
Unpacking replacement e2fslibs ...
Processing triggers for man-db ...
Errors were encountered while processing:
 /var/cache/apt/archives/memtest86+_4.00-2.3_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)
A package failed to install.  Trying to recover:

I have a relative simple setup.There is a sda and sdb. sda has sda1 which is 
/boot and sda2 which is crypted and then part one of an lvm. sdb1 has only 
crypted and then part 2 of the lvm. Inside the lvm is a "root-lvm" which is / 
and a swap partition.

The root partition is a simple ext4 partition. The device is /dev/dm-3 and it 
for example linked in /dev/root and /dev/block/254:3 and /dev/lvm1/root-lvm 
and lvm1-root--lvm

It must have been worked in the past because I updated grub in the past. I've 
also tried to run `sudo dpkg-reconfigure grub-common` and mark all my devices 
to install grub into their boot sectors, but at the end I only get

Installation finished. No error reported.
Installation finished. No error reported.
/usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?).

So first thing: I don't understand why grub should be interested in my / ... 
there is a /boot mounted.

$ mount|grep boot
/dev/sda1 on /boot type ext3 (rw)

I've also tried grub-probe from unstable and it just says:
./grub-probe: error: no such disk.

--- System information. ---
Architecture: i386
Kernel:       Linux 2.6.34-1-686

Debian Release: squeeze/sid
  500 testing         ftp.debian.org

--- Package information. ---
Depends             (Version) | Installed
=============================-+-=============
base-files        (>= 4.0.1~) | 5.7
dpkg             (>= 1.15.4)  | 1.15.7.2
 OR install-info              | 4.13a.dfsg.1-5
 OR dpkg         (<= 1.14.25) | 1.15.7.2
libc6                (>= 2.3) | 2.11.1-3
libfreetype6       (>= 2.2.1) | 2.3.11-1
zlib1g           (>= 1:1.1.4) | 1:1.2.3.4.dfsg-3
gettext-base                  | 0.17-11


Recommends      (Version) | Installed
=========================-+-===========
os-prober       (>= 1.33) | 1.35


Suggests           (Version) | Installed
============================-+-===========
multiboot-doc                | 
grub-emu                     |