[Bug 554307] Re: linux-boot-prober yields wrong uuid for kernel root parameter

[V[i]ctor]

Yes, the bug appears on 14.04 LTS release. The partition in question is
not mounted via /etc/fstab.

To understand what's going on I'd better give you blkid output with some
my comments:

$ blkid /dev/sda*
/dev/sda1: UUID="66ECBF91ECBF5A4F" TYPE="ntfs" 
/dev/sda10: UUID="04db7581-6256-408c-969b-27847b90f5e3" TYPE="ext4" # Ubuntu 14.04, my main OS, all the scripts I run, I run here
/dev/sda2: UUID="425ec35d-cc19-438a-aa30-ea3b0beee6ae" TYPE="ext4" # /boot partition for both Ubuntu systems
/dev/sda5: UUID="f728b87c-d0fa-4419-a55a-aee66dead3c4" TYPE="ext4" # old Ubuntu 10.04, I can't boot it because of the current bug (but I fixed grub.cfg later on)
/dev/sda6: UUID="b862754b-5a40-4412-87ac-eb7e846be4bb" TYPE="ext4" # my /home for both Ubuntus
/dev/sda7: UUID="e1eb1b01-8c1a-4237-85ec-e69255f2a73e" TYPE="ext4" 
/dev/sda8: UUID="b30c59b6-fc31-4a06-b04b-a13d9f898c1c" TYPE="swap" 
/dev/sda9: UUID="70EFAAAD68BA7261" TYPE="ntfs"

I also found that linux-boot-prober uses grub.cfg to get the data.

I ran it 3 times: without grub.cfg in /boot/grub/, with the grub.cfg
generated by update-grub script (which uses linux-boot-prober, that's
where this bug affects grub2 package) and with fixed by hand grub.cfg.
You can see all 3 outputs in the attached file. (I have partial russian
locale, so cyrillic с there stands for the word "with".)

You may also want to see my grub.cfg file before and after my fix. The
old one wasn't saved, so I regenerated it running update-grub several
times (it's a huge mess there right  now). Both fixed one and
regenerated one are in attachment.

As far as I found out, linux-boot-prober parses grub.cfg assuming there
are no other operating systems which use the same /boot partition. When
it does so, it just finds all linux menuentries and prints all them out,
with root partitions from the corresponding menuentries.

So the actual bug is, linux-boot-prober prints out the wrong kernels
from grub.cfg, and the update-grub script uses this incorrect data from
linux-boot-prober to generate messed up grub.cfg. In the update-grub
script there is actually no bug, just not super-safe-checking-everything
behaviour, so I'll leave the bug from grub2 as a duplicate.

** Attachment added: "attachments"
   https://bugs.launchpad.net/ubuntu/+source/os-prober/+bug/554307/+attachment/4432503/+files/attachments

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https://bugs.launchpad.net/bugs/554307

Title:
  linux-boot-prober yields wrong uuid for kernel root parameter

Status in os-prober package in Ubuntu:
  Incomplete

Bug description:
  Binary package hint: os-prober

  My Partitions:
  sda5 swap
  sda6 lucid
  sda7 karmic

  linux-boot-prober doesn't take the root partition as kernel root
  paraameter for my karmic installation.

  matthias at netbook:/boot/grub$ ls -l /dev/disk/by-uuid/
  insgesamt 0
  lrwxrwxrwx 1 root root 10 2010-04-02 23:08 199233d9-7174-445d-81df-eb9c95af871f -> ../../sda7
  lrwxrwxrwx 1 root root 10 2010-04-02 23:08 1E4F-1E00 -> ../../sda2
  lrwxrwxrwx 1 root root 10 2010-04-02 23:08 523cd06e-f460-4c88-b1e9-5382df4e5d37 -> ../../sda6
  lrwxrwxrwx 1 root root 10 2010-04-02 23:08 82A8C040A8C03507 -> ../../sda1
  lrwxrwxrwx 1 root root 10 2010-04-02 23:08 837c2ad3-a209-4668-b864-a79320c5094b -> ../../sda5

  matthias at netbook:/boot/grub$ linux-boot-prober /dev/disk/by-uuid/199233d9-7174-445d-81df-eb9c95af871f
  unshare failed: Operation not permitted
  /dev/disk/by-uuid/199233d9-7174-445d-81df-eb9c95af871f:/dev/disk/by-uuid/199233d9-7174-445d-81df-eb9c95af871f:Ubuntu, Linux 2.6.31-16-generic:/boot/vmlinuz-2.6.31-16-generic:/boot/initrd.img-2.6.31-16-generic:root=UUID=523cd06e-f460-4c88-b1e9-5382df4e5d37 ro quiet splash
  ...

  I suspect that when I try to boot my karmic, it boots the karmic
  kernel with lucid userland -> nothing works.

  ProblemType: Bug
  DistroRelease: Ubuntu 10.04
  Package: os-prober 1.36
  ProcVersionSignature: Ubuntu 2.6.32-19.28-generic 2.6.32.10+drm33.1
  Uname: Linux 2.6.32-19-generic i686
  Architecture: i386
  Date: Sat Apr  3 01:15:03 2010
  ProcEnviron:
   LANG=de_DE.UTF-8
   SHELL=/bin/bash
  SourcePackage: os-prober

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