[Bug 445367] [NEW] os-prober entries do not use correct /boot device

[Marien Zwart]

Public bug reported:

Binary package hint: grub2

I'm encountering this on a system using lvm with a separate /boot
partition outside of lvm used by jaunty but no separate /boot for
karmic, but I think it will affect every system with grub 1 on a
separate /boot partition, not just those also using lvm.

"sudo os-prober" gives me:

/dev/sda1:Microsoft Windows XP Home Edition:Windows:chain
/dev/mapper/main-jaunty_chroot:Ubuntu 9.04 (9.04):Ubuntu:linux
/dev/mapper/main-root:Ubuntu 9.04 (9.04):Ubuntu1:linux

which as far as I know is correct: main/jaunty_chroot is an sbuild-lvm
chroot, main/root is a regular jaunty install.

"sudo linux-boot-prober /dev/mapper/main-root" gives me:

/dev/mapper/main-root:/dev/sda2:Ubuntu 9.04, kernel 2.6.28-15-generic:/boot/vmlinuz-2.6.28-15-generic:/boot/initrd.img-2.6.28-15-generic:root=/dev/mapper/main-root ro quiet splash
/dev/mapper/main-root:/dev/sda2:Ubuntu 9.04, kernel 2.6.28-15-generic (recovery mode):/boot/vmlinuz-2.6.28-15-generic:/boot/initrd.img-2.6.28-15-generic:root=/dev/mapper/main-root ro single
/dev/mapper/main-root:/dev/sda2:Ubuntu 9.04, kernel 2.6.28-3-rt:/boot/vmlinuz-2.6.28-3-rt:/boot/initrd.img-2.6.28-3-rt:root=/dev/mapper/main-root ro quiet splash
/dev/mapper/main-root:/dev/sda2:Ubuntu 9.04, kernel 2.6.28-3-rt (recovery mode):/boot/vmlinuz-2.6.28-3-rt:/boot/initrd.img-2.6.28-3-rt:root=/dev/mapper/main-root ro single
/dev/mapper/main-root:/dev/sda2:Ubuntu 9.04, memtest86+:/boot/memtest86+.bin::

which again I think is correct. Notice /dev/sda2 is my separate /boot
partition.

However /etc/grub/30_os-prober completely ignores the /boot partition
information supplied by linux-os-prober ($LBOOT in the script) and
generates a grub.cfg that looks for the kernel on the root device, which
does not work. That is: it generates entries like:

menuentry "Ubuntu 9.04, kernel 2.6.28-15-generic (on /dev/mapper/main-root)" {
	insmod lvm
	insmod ext2
	set root=(main-root)
	search --no-floppy --fs-uuid --set 096600f3-ffce-445c-8cd7-588461a4894e
	linux /boot/vmlinuz-2.6.28-15-generic root=/dev/mapper/main-root ro quiet splash
	initrd /boot/initrd.img-2.6.28-15-generic
}

while a manually added entry that works is:

menuentry "Ubuntu 9.04, kernel 2.6.28-15-generic (on /dev/mapper/main-root)" {
	insmod lvm
	insmod ext2
	set root=(hd0,2)
	linux /vmlinuz-2.6.28-15-generic root=/dev/mapper/main-root ro quiet splash
	initrd /initrd.img-2.6.28-15-generic
}

Notice that just changing the prepare_grub_to_access_device call to use
${LBOOT} instead of ${DEVICE} does not quite suffice: the leading /boot
component needs to be removed from the initrd and vmlinuz paths too.
Since it looks like /usr/lib/linux-boot-probes/mounted/40grub actually
prepends /boot if there's a separate /boot partition it might make sense
to have linux-boot-probe pass the path grub uses unchanged (instead of
having another check for a separate /boot partition to chop off the path
component 40grub added).

ProblemType: Bug
Architecture: i386
Date: Wed Oct  7 13:24:42 2009
DistroRelease: Ubuntu 9.10
Package: grub2 (not installed)
ProcEnviron:
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.31-12.39-generic
SourcePackage: grub2
Uname: Linux 2.6.31-12-generic i686

** Affects: grub2 (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: apport-bug i386

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os-prober entries do not use correct /boot device
https://bugs.launchpad.net/bugs/445367
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