os-prober 1.40 doesn't detect another ubuntu installation anymore

[Nicolas DERIVE]

Binary package hint: os-prober

On Natty development release, os-prober doesn't detect another Ubuntu installation on a separate partition, whereas previous maverick version does. It's clearly a regression.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: os-prober 1.40
ProcVersionSignature: Ubuntu 2.6.36-1.7-generic-pae 2.6.36
Uname: Linux 2.6.36-1-generic-pae i686
NonfreeKernelModules: nvidia
Architecture: i386
CheckboxSubmission: c4273c0f4f2b8d26cd6bf31cadfd2912
CheckboxSystem: a871981cb5bdf4d6ebd55be46becf77e
Date: Sat Nov 13 11:49:07 2010
EcryptfsInUse: Yes
ProcEnviron:
 SHELL=/bin/bash
 LANG=fr_FR.UTF-8
 LANGUAGE=fr_FR:fr:en_GB:en
SourcePackage: os-prober

[Colin Watson (cjwatson)]

Can you try mounting the filesystem in question, unmounting it straight away, and then running os-prober? If this works around the problem (I'm not suggesting it as a permanent solution), then this is the same as bug 683355.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Axel Beckert (xtaran)]

Hi Colin,

yes, this bug happens for me, too, with the os-prober versions from natty (1.44ubuntu1) and oneiric (1.49ubuntu1), but not from maverick (1.39). Except that the other OS is a Debian Sid and not another Ubuntu. But I don't think this makes a difference here.

Mounting the root as well as the /boot filesystem neither shows a warning about an uncleanly unmounted filesystem.

It seems that os-prober works fine, but linux-boot-prober does not. The other Linux on this box has /boot on /dev/sda1 and / on /dev/sda5. linux-boot-prober /dev/sda5 just returns nothing while linux-boot-prober /dev/sda1 finds all kernels, but claims the root filesystem is /dev/sda1 while it is /dev/sda5 as os-prober correctly found out.

U 53/0/2 root@loadrunner:pts/0 03:14:44 [~] # os-prober /dev/sda1
/dev/sda5:Debian GNU/Linux (wheezy/sid):Debian:linux
U 54/0/2 root@loadrunner:pts/0 03:14:52 [~] # os-prober /dev/sda5
/dev/sda5:Debian GNU/Linux (wheezy/sid):Debian:linux
U 55/0/2 root@loadrunner:pts/0 03:14:58 [~] # linux-boot-prober /dev/sda1
/dev/sda1:/dev/sda1::/vmlinuz-2.6.31-1-686:/initrd.img-2.6.31-1-686:root=/dev/sda1
/dev/sda1:/dev/sda1::/vmlinuz-2.6.32-4-686:/initrd.img-2.6.32-4-686:root=/dev/sda1
/dev/sda1:/dev/sda1::/vmlinuz-2.6.32-5-686:/initrd.img-2.6.32-5-686:root=/dev/sda1
/dev/sda1:/dev/sda1::/vmlinuz-2.6.33-2-686:/initrd.img-2.6.33-2-686:root=/dev/sda1
/dev/sda1:/dev/sda1::/vmlinuz-2.6.34-1-686:/initrd.img-2.6.34-1-686:root=/dev/sda1
/dev/sda1:/dev/sda1::/vmlinuz-2.6.35-trunk-686:/initrd.img-2.6.35-trunk-686:root=/dev/sda1
/dev/sda1:/dev/sda1::/vmlinuz-2.6.36-trunk-686:/initrd.img-2.6.36-trunk-686:root=/dev/sda1
/dev/sda1:/dev/sda1::/vmlinuz-2.6.37-2-686:/initrd.img-2.6.37-2-686:root=/dev/sda1
/dev/sda1:/dev/sda1::/vmlinuz-2.6.37-trunk-686:/initrd.img-2.6.37-trunk-686:root=/dev/sda1
/dev/sda1:/dev/sda1::/vmlinuz-2.6.38-2-686:/initrd.img-2.6.38-2-686:root=/dev/sda1
/dev/sda1:/dev/sda1::/vmlinuz-2.6.39-1-686-pae:/initrd.img-2.6.39-1-686-pae:root=/dev/sda1
/dev/sda1:/dev/sda1::/vmlinuz-2.6.39-2-686-pae:/initrd.img-2.6.39-2-686-pae:root=/dev/sda1
/dev/sda1:/dev/sda1::/vmlinuz-3.0.0-1-686-pae:/initrd.img-3.0.0-1-686-pae:root=/dev/sda1
/dev/sda1:/dev/sda1::/vmlinuz-3.0.0-rc6-686-pae:/initrd.img-3.0.0-rc6-686-pae:root=/dev/sda1
/dev/sda1:/dev/sda1::/vmlinuz-3.1.0-rc4-686-pae:/initrd.img-3.1.0-rc4-686-pae:root=/dev/sda1
/dev/sda1:/dev/sda1::/vmlinuz-3.1.0-rc6-686-pae:/initrd.img-3.1.0-rc6-686-pae:root=/dev/sda1
/dev/sda1:/dev/sda1::/vmlinuz-3.1.0-rc7-686-pae:/initrd.img-3.1.0-rc7-686-pae:root=/dev/sda1
U 56/0/2 root@loadrunner:pts/0 03:15:05 [~] # linux-boot-prober /dev/sda5
U 57/0/2 root@loadrunner:pts/0 03:15:14 [~] #

[Axel Beckert (xtaran)]

With the os-prober version from maverick (1.39) installed on oneiric, it looks like this:

U 58/0/2 root@loadrunner:pts/0 03:18:30 [~] # os-prober /dev/sda5
/dev/sda5:Debian GNU/Linux (wheezy/sid):Debian:linux
U 59/0/2 root@loadrunner:pts/0 03:18:38 [~] # linux-boot-prober /dev/sda5
/dev/sda5:/dev/sda1:Debian GNU/Linux, kernel 3.1.0-rc7-686-pae:/boot/vmlinuz-3.1.0-rc7-686-pae:/boot/initrd.img-3.1.0-rc7-686-pae:root=UUID=42e2321b-f075-42d8-8223-d13a9d45f3ab ro
/dev/sda5:/dev/sda1:Debian GNU/Linux, kernel 3.1.0-rc7-686-pae (single-user mode):/boot/vmlinuz-3.1.0-rc7-686-pae:/boot/initrd.img-3.1.0-rc7-686-pae:root=UUID=42e2321b-f075-42d8-8223-d13a9d45f3ab ro single
/dev/sda5:/dev/sda1:Debian GNU/Linux, kernel 3.1.0-rc6-686-pae:/boot/vmlinuz-3.1.0-rc6-686-pae:/boot/initrd.img-3.1.0-rc6-686-pae:root=UUID=42e2321b-f075-42d8-8223-d13a9d45f3ab ro
/dev/sda5:/dev/sda1:Debian GNU/Linux, kernel 3.1.0-rc6-686-pae (single-user mode):/boot/vmlinuz-3.1.0-rc6-686-pae:/boot/initrd.img-3.1.0-rc6-686-pae:root=UUID=42e2321b-f075-42d8-8223-d13a9d45f3ab ro single
/dev/sda5:/dev/sda1:Debian GNU/Linux, kernel 3.1.0-rc4-686-pae:/boot/vmlinuz-3.1.0-rc4-686-pae:/boot/initrd.img-3.1.0-rc4-686-pae:root=UUID=42e2321b-f075-42d8-8223-d13a9d45f3ab ro
/dev/sda5:/dev/sda1:Debian GNU/Linux, kernel 3.1.0-rc4-686-pae (single-user mode):/boot/vmlinuz-3.1.0-rc4-686-pae:/boot/initrd.img-3.1.0-rc4-686-pae:root=UUID=42e2321b-f075-42d8-8223-d13a9d45f3ab ro single
/dev/sda5:/dev/sda1:Debian GNU/Linux, kernel 3.0.0-1-686-pae:/boot/vmlinuz-3.0.0-1-686-pae:/boot/initrd.img-3.0.0-1-686-pae:root=UUID=42e2321b-f075-42d8-8223-d13a9d45f3ab ro
/dev/sda5:/dev/sda1:Debian GNU/Linux, kernel 3.0.0-1-686-pae (single-user mode):/boot/vmlinuz-3.0.0-1-686-pae:/boot/initrd.img-3.0.0-1-686-pae:root=UUID=42e2321b-f075-42d8-8223-d13a9d45f3ab ro single
/dev/sda5:/dev/sda1:Debian GNU/Linux, kernel 3.0.0-rc6-686-pae:/boot/vmlinuz-3.0.0-rc6-686-pae:/boot/initrd.img-3.0.0-rc6-686-pae:root=UUID=42e2321b-f075-42d8-8223-d13a9d45f3ab ro
/dev/sda5:/dev/sda1:Debian GNU/Linux, kernel 3.0.0-rc6-686-pae (single-user mode):/boot/vmlinuz-3.0.0-rc6-686-pae:/boot/initrd.img-3.0.0-rc6-686-pae:root=UUID=42e2321b-f075-42d8-8223-d13a9d45f3ab ro single
/dev/sda5:/dev/sda1:Debian GNU/Linux, kernel 2.6.39-2-686-pae:/boot/vmlinuz-2.6.39-2-686-pae:/boot/initrd.img-2.6.39-2-686-pae:root=UUID=42e2321b-f075-42d8-8223-d13a9d45f3ab ro
/dev/sda5:/dev/sda1:Debian GNU/Linux, kernel 2.6.39-2-686-pae (single-user mode):/boot/vmlinuz-2.6.39-2-686-pae:/boot/initrd.img-2.6.39-2-686-pae:root=UUID=42e2321b-f075-42d8-8223-d13a9d45f3ab ro single
/dev/sda5:/dev/sda1:Debian GNU/Linux, kernel 2.6.39-1-686-pae:/boot/vmlinuz-2.6.39-1-686-pae:/boot/initrd.img-2.6.39-1-686-pae:root=UUID=42e2321b-f075-42d8-8223-d13a9d45f3ab ro
/dev/sda5:/dev/sda1:Debian GNU/Linux, kernel 2.6.39-1-686-pae (single-user mode):/boot/vmlinuz-2.6.39-1-686-pae:/boot/initrd.img-2.6.39-1-686-pae:root=UUID=42e2321b-f075-42d8-8223-d13a9d45f3ab ro single
/dev/sda5:/dev/sda1:Debian GNU/Linux, kernel 2.6.38-2-686:/boot/vmlinuz-2.6.38-2-686:/boot/initrd.img-2.6.38-2-686:root=UUID=42e2321b-f075-42d8-8223-d13a9d45f3ab ro
/dev/sda5:/dev/sda1:Debian GNU/Linux, kernel 2.6.38-2-686 (single-user mo...

[bitinerant (bitinerant)]

I, too, have "lost" my other Ubuntu partition. I installed 12.04 on sda1 using Btrfs; it booted fine. Then I installed another 12.04 on sda2 (/boot) and sda3 (swap) and sda4 (/), and it boots fine, but now I can't boot from sda1. Mounting and then unmounting sda1 as suggested in comment #2 does not help.

$ sudo fdisk -l /dev/sda

Disk /dev/sda: 128.0 GB, 128035676160 bytes
255 heads, 63 sectors/track, 15566 cylinders, total 250069680 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x00076ab2

   Device Boot Start End Blocks Id System
/dev/sda1 * 2048 13672447 6835200 83 Linux
/dev/sda2 * 13672448 14258175 292864 83 Linux
/dev/sda3 14258176 24023039 4882432 82 Linux swap / Solaris
/dev/sda4 24023040 250068991 113022976 83 Linux
$ sudo os-prober
$

[bitinerant (bitinerant)]

Comment #2 of http://ubuntuforums.org/showthread.php?t=1969614 says that renaming the grub.cfg on the _hidden partition_ allows update-grub to work, but this did not help in my situation.