grub2 requires non-existent /dev/root (Bug #341)

$ sorcery -v
1.15.1

$ gaze version grub2 udev
Grimoire Section Spell Grimoire Version Installed Version
-------- ------- ----- ---------------- -----------------
test disk grub2 1.99 1.99
test disk udev 175 175

GRUB now uses /proc/self/mountinfo for determining the root device (http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=627587). I have never specified /dev/root as any valid device.

$ cat /proc/self/mountinfo
13 1 8:7 / / rw,relatime - ext4 /dev/root rw,user_xattr,acl,barrier=1,data=ordered
14 13 0:3 / /proc rw,relatime - proc proc rw
15 13 0:13 / /sys rw,relatime - sysfs sysfs rw
16 13 0:14 / /run rw,relatime - tmpfs tmpfs rw
17 13 0:15 / /dev rw,relatime - ramfs none rw
18 17 0:8 / /dev/pts rw,relatime - devpts devpts rw,mode=600
19 13 8:5 / /boot rw,relatime - ext4 /dev/sda5 rw,user_xattr,acl,barrier=1,data=ordered
20 13 8:6 / /home rw,relatime - ext4 /dev/sda6 rw,user_xattr,acl,barrier=1,data=ordered
21 13 8:2 / /mnt/windows rw,nosuid,nodev,noexec,relatime - fuseblk /dev/sda2 rw,user_id=0,group_id=0,default_permissions,allow_other,blksize=4096
22 17 0:16 / /dev/shm rw,relatime - tmpfs tmpfs rw
23 14 0:17 / /proc/sys/fs/binfmt_misc rw,relatime - binfmt_misc none rw
25 15 0:18 / /sys/fs/fuse/connections rw,relatime - fusectl fusectl rw

$ cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-3.2.0 root=/dev/sda7 ro

With the latest grub2 updated to 1.99, my grub-mkconfig fails to generate a new menu:

1. grub-mkconfig > /boot/grub/grub.cfg
   /usr/sbin/grub-probe: error: cannot stat `/dev/root'.

A possible patch to fix for "broken" udevs is: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=627587#92 (attached as fix-udev.patch) or the Debian submitted fix at http://anonscm.debian.org/loggerhead/pkg-grub/trunk/grub/revision/2435. I have not tested it.

If people do not notice this during their upgrade of grub, then they'll have an empty /boot/grub/grub.cfg and have to do some recovery work to boot.