Bug#505137: grub-common: grub-probe returns fat for ext3 root fs

[Scott Ashcroft]

Package: grub-common
Version: 1.96+20080724-11
Severity: important


grub-probe misdetects the root fs of one of my PCs (works fine on all others).

lisa:/# grub-probe --target=fs /
fat

lisa:/# sfdisk -l /dev/sda

Disk /dev/sda: 19452 cylinders, 255 heads, 63 sectors/track
Units = cylinders of 8225280 bytes, blocks of 1024 bytes, counting from 0

   Device Boot Start     End   #cyls    #blocks   Id  System
/dev/sda1   *      0+  19080   19081- 153268101   83  Linux
/dev/sda2      19081   19451     371    2980057+   5  Extended
/dev/sda3          0       -       0          0    0  Empty
/dev/sda4          0       -       0          0    0  Empty
/dev/sda5      19081+  19451     371-   2980026   82  Linux swap / Solaris

lisa:/# mount
/dev/sda1 on / type ext3 (rw,errors=remount-ro)
tmpfs on /lib/init/rw type tmpfs (rw,nosuid,mode=0755)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
procbususb on /proc/bus/usb type usbfs (rw)
udev on /dev type tmpfs (rw,mode=0755)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=620)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc (rw,noexec,nosuid,nodev)

It looks like grub-probe runs the FAT checks before the EXT2 check and I just happen to hit a false positive.

Hopefully 512 bytes of the partition should be enough to debug this?

sa:/# hexdump -Cn 512 /dev/sda1
00000000  eb 4a 90 00 65 6c 6c 20  38 2e 30 00 02 04 01 00  |.J..ell 8.0.....|
00000010  02 00 02 00 00 f8 4f 00  3f 00 ff 00 3f 00 00 00  |......O.?...?...|
00000020  86 39 01 00 80 00 29 09  08 d6 07 44 65 6c 6c 55  |.9....)....DellU|
00000030  74 69 6c 69 74 79 00 41  54 31 36 20 20 20 00 00  |tility.AT16   ..|
00000040  00 00 00 00 00 00 00 00  00 00 00 30 33 c0 8e d0  |...........03...|
00000050  bc 00 07 fc b9 80 00 8e  d8 be 00 7c b8 00 20 8e  |...........|.. .|
00000060  c0 33 ff f3 66 a5 ea 6b  00 00 20 8e d8 b8 01 02  |.3..f..k.. .....|
00000070  b9 01 00 b6 00 8a 16 24  00 bb 00 02 cd 13 0f 82  |.......$........|
00000080  e0 00 80 3e c2 03 06 74  0e c6 06 c2 03 06 b8 01  |...>...t........|
00000090  03 cd 13 0f 82 cb 00 66  0f b7 06 16 00 66 d1 e0  |.......f.....f..|
000000a0  66 40 66 03 06 1c 00 66  a3 3e 00 8b 2e 11 00 89  |f at f....f.>......|
000000b0  2e 44 00 c1 ed 04 e8 cb  00 4d 75 fa b9 0b 00 be  |.D.......Mu.....|
000000c0  ea 01 8b fd f3 a6 74 0f  83 c5 20 ff 0e 44 00 75  |......t... ..D.u|
000000d0  eb be e0 01 e9 8e 00 26  8b 46 1a a3 46 00 66 a1  |.......&.F..F.f.|
000000e0  1c 00 66 40 66 a3 3e 00  c7 06 48 00 00 00 8b 2e  |..f at f.>...H.....|
000000f0  16 00 e8 8f 00 4d 75 fa  c7 06 4a 00 70 00 c7 06  |.....Mu...J.p...|
00000100  48 00 00 00 66 0f b7 06  46 00 66 83 e8 02 66 0f  |H...f...F.f...f.|
00000110  b6 0e 0d 00 66 f7 e1 66  0f b7 0e 16 00 66 d1 e1  |....f..f.....f..|
00000120  66 41 66 03 0e 1c 00 66  03 c1 66 0f b7 0e 11 00  |fAf....f..f.....|
00000130  66 c1 e9 04 66 03 c1 66  a3 3e 00 0f b6 2e 0d 00  |f...f..f.>......|
00000140  e8 41 00 4d 75 fa 8b 36  46 00 b8 00 30 d1 e6 73  |.A.Mu..6F...0..s|
00000150  03 05 00 10 8e c0 26 ad  3d f8 ff 73 0d a3 46 00  |......&.=..s..F.|
00000160  eb a2 be d5 01 e8 0d 00  eb fe 8a 16 24 00 33 ed  |............$.3.|
00000170  ea 00 00 70 00 ac 3c 00  74 09 b4 0e bb 07 00 cd  |...p..<.t.......|
00000180  10 eb f2 c3 66 a1 3e 00  66 33 d2 66 0f b7 0e 18  |....f.>.f3.f....|
00000190  00 66 f7 f1 fe c2 88 16  25 00 32 d2 66 0f b7 0e  |.f......%.2.f...|
000001a0  1a 00 66 f7 f1 8a f2 8b  c8 b8 01 02 c0 e5 06 0a  |..f.............|
000001b0  2e 25 00 86 e9 8a 16 24  00 c4 1e 48 00 cd 13 72  |.%.....$...H...r|
000001c0  a1 66 ff 06 3e 00 81 06  48 00 00 02 75 06 81 06  |.f..>...H...u...|
000001d0  4a 00 00 10 c3 44 69 73  6b 20 65 72 72 6f 72 00  |J....Disk error.|
000001e0  4e 6f 20 6c 6f 61 64 65  72 00 44 45 4c 4c 42 49  |No loader.DELLBI|
000001f0  4f 20 42 49 4e 00 00 00  00 00 00 00 00 00 00 00  |O BIN...........|
00000200

Maybe the order of fs detection should be changed to look for ext2 first?

-- System Information:
Debian Release: lenny/sid
  APT prefers testing
  APT policy: (500, 'testing')
Architecture: amd64 (x86_64)

Kernel: Linux 2.6.27.5 (SMP w/2 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/bash

Versions of packages grub-common depends on:
ii  base-files                    4.0.5      Debian base system miscellaneous f
ii  libc6                         2.7-15     GNU C Library: Shared libraries

grub-common recommends no packages.

Versions of packages grub-common suggests:
pn  multiboot-doc                 <none>     (no description available)

-- no debconf information