grub-mkrelpath produce incorrect paths if /boot is a bind mount

[Kasper Dupont]

grub-mkconfig uses grub-mkrelpath to find out which paths to put in grub.cfg, but in some cases grub-mkrelpath produce an incorrect output.

If / and /boot are both mountpoints of different directories from the same physical file system, grub-mkrelpath will use the wrong entry from /proc/self/mountinfo. It should use the entry for /boot to produce the correct path, but it picks the entry for / when given a path under /boot.

For example if /proc/self/mountinfo contains:
20 1 8:1 /lucid / rw,relatime - ext4 ....
26 20 8:1 /boot /boot rw,relatime - ext4 ....

Then running "grub-mkrelpath /boot/grub" outputs /lucid/boot/grub, but it should have output /boot/grub.

ProblemType: Bug
DistroRelease: Ubuntu 11.04
Package: grub-common 1.99~rc1-13ubuntu3 [modified: usr/bin/grub-mkrelpath]
ProcVersionSignature: Ubuntu 2.6.38-8.42-generic 2.6.38.2
Uname: Linux 2.6.38-8-generic i686
NonfreeKernelModules: nvidia
Architecture: i386
Date: Tue Mar 20 00:00:30 2012
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 11.04 "Natty Narwhal" - Release i386 (20110427.1)
ProcEnviron:
 LANGUAGE=en_US:en
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: grub2
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

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

[Marcus Tomlinson (marcustomlinson)]

This release of Ubuntu is no longer receiving maintenance updates. If this is still an issue on a maintained version of Ubuntu please let us know.

[Launchpad Janitor (janitor)]

[Expired for grub2 (Ubuntu) because there has been no activity for 60 days.]