Custom 3.2.0-rc7+ vmlinuz will not load when grub2 1.99-14ubuntu2 fails to access the WUBI loop-mounted root EXT3 filesystem

[Miles Lane]

I have a 3.2.0-6 Ubuntu 12.04 kernel that successfully boots.
Every time I try to build and boot a Linus GIT tree custom kernel it fails to boot.
I have tried every combination of building EXT2, EXT3 and EXT4 support in the kernel.

I am running a WUBI install (the root filesystem is located in a
loopback mounted file on my Windows 7 NTFS filesystem). The
distribution is Ubuntu 11.10 upgraded to 12.04 (Precise Pangolin).

I set debug=all at the Grub2 command line and tried to load my custom kernel.
The point where the failure occurs is when Grub checks to see whether
the root filesystem is ext2:

kern/disk.c:245: Opening 'loop0'.
kern/fs.c:54: Detecting tarfs...
failed
kern/fs.c:54: Detecting iso9660...
failed
kern/fs.c:54: Detecting ext2...
failed

Then I tried to load the Ubuntu vmlinuz-3.2.0-6-generic
And it gave:

kern/fs.c:54: Detecting ext2...
loader/i386/linux.c:201 real_size = 1800, prot_size = 4b1000, mmap_size = 2000

So, I am confused whether this problem is:
  1. A failure of Grub2 resulting from some flaw that causes any
custom kernel installation to fail to boot because this detection
fails in Grub2.
  2. A failure of Grub2 to successfully detect the loop mounted
filesystem at ext2 because there is a problem with a driver in Linus'
GIT tree.

                 Boot Info Script 0.60 from 17 May 2011

============================= Boot Info Summary: ===============================

 => Windows is installed in the MBR of /dev/sda.

sda1: __________________________________________________________________________

   File system: ntfs
   Boot sector type: Windows Vista/7
   Boot sector info: No errors found in the Boot Parameter Block.
   Operating System:
   Boot files: /bootmgr /Boot/BCD

sda2: __________________________________________________________________________

   File system: ntfs
   Boot sector type: Windows Vista/7
   Boot sector info: No errors found in the Boot Parameter Block.
   Operating System: Windows 7
   Boot files: /Windows/System32/winload.exe /wubildr
                      /ubuntu/winboot/wubildr /wubildr.mbr
                      /ubuntu/winboot/wubildr.mbr /ubuntu/disks/root.disk
                      /ubuntu/disks/swap.disk

sda2/Wubi: _____________________________________________________________________

   File system: ext3
   Boot sector type: -
   Boot sector info:
   Operating System: Ubuntu precise (development
                      branch)
   Boot files: /boot/grub/grub.cfg /etc/fstab

============================ Drive/Partition Info: =============================

Drive: sda _____________________________________________________________________

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes

Partition Boot Start Sector End Sector # of Sectors Id System

/dev/sda1 * 2,048 206,847 204,800 7 NTFS /
exFAT / HPFS
/dev/sda2 206,848 976,771,071 976,564,224 7 NTFS /
exFAT / HPFS

"blkid" output: ________________________________________________________________

Device UUID TYPE LABEL

/dev/loop0 e4635099-89df-4538-8a43-cefac4a53b3b ext3
/dev/sda1 FC700CEB700CAE88 ntfs
System Reserved
/dev/sda2 9A200E69200E4CA7 ntfs

================================ Mount points: =================================

Device Mount_Point Type Options

/dev/loop0 / ext3 (rw,commit=0,commit=0)
/dev/sda2 /host fuseblk
(rw,nosuid,nodev,relatime,user_id=0,group_id=0,allow_other,blksize=4096)

======================== sda2/Wubi/boot/grub/grub.cfg: =========================

--------------------------------------------------------------------------------
#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
menuentry 'Ubuntu, with Linux 3.2.0-7-generic' --class ubuntu --class
gnu-linux --class gnu --class os {
       set gfxpayload=$linux_gfx_mode
       insmod part_msdos
       insmod ntfs
       set root='(hd0,msdos2)'
       search --no-floppy --fs-uuid --set=root 9A200E69200E4CA7
       loopback loop0 /ubuntu/disks/root.disk
       set root=(loop0)
       linux /boot/vmlinuz-3.2.0-7-generic root=UUID=9A200E69200E4CA7
loop=/ubuntu/disks/root.disk ro quiet splash vt.handoff=7
       initrd /boot/initrd.img-3.2.0-7-generic
}
menuentry 'Ubuntu, with Linux 3.2.0-7-generic (recovery mode)' --class
ubuntu --class gnu-linux --class gnu --class os {
       set gfxpayload=$linux_gfx_mode
       insmod part_msdos
       insmod ntfs
       set root='(hd0,msdos2)'
       search --no-floppy --fs-uuid --set=root 9A200E69200E4CA7
       loopback loop0 /ubuntu/disks/root.disk
       set root=(loop0)
       echo 'Loading Linux 3.2.0-7-generic ...'
       linux /boot/vmlinuz-3.2.0-7-generic root=UUID=9A200E69200E4CA7
loop=/ubuntu/disks/root.disk ro recovery nomodeset
       echo 'Loading initial ramdisk ...'
       initrd /boot/initrd.img-3.2.0-7-generic
}
submenu "Previous Linux versions" {
menuentry 'Ubuntu, with Linux 3.2.0-6-generic' --class ubuntu --class
gnu-linux --class gnu --class os {
       set gfxpayload=$linux_gfx_mode
       insmod part_msdos
       insmod ntfs
       set root='(hd0,msdos2)'
       search --no-floppy --fs-uuid --set=root 9A200E69200E4CA7
       loopback loop0 /ubuntu/disks/root.disk
       set root=(loop0)
       linux /boot/vmlinuz-3.2.0-6-generic root=UUID=9A200E69200E4CA7
loop=/ubuntu/disks/root.disk ro quiet splash vt.handoff=7
       initrd /boot/initrd.img-3.2.0-6-generic
}
menuentry 'Ubuntu, with Linux 3.2.0-6-generic (recovery mode)' --class
ubuntu --class gnu-linux --class gnu --class os {
       set gfxpayload=$linux_gfx_mode
       insmod part_msdos
       insmod ntfs
       set root='(hd0,msdos2)'
       search --no-floppy --fs-uuid --set=root 9A200E69200E4CA7
       loopback loop0 /ubuntu/disks/root.disk
       set root=(loop0)
       echo 'Loading Linux 3.2.0-6-generic ...'
       linux /boot/vmlinuz-3.2.0-6-generic root=UUID=9A200E69200E4CA7
loop=/ubuntu/disks/root.disk ro recovery nomodeset
       echo 'Loading initial ramdisk ...'
       initrd /boot/initrd.img-3.2.0-6-generic
}
menuentry 'Ubuntu, with Linux 3.2.0-rc7+' --class ubuntu --class
gnu-linux --class gnu --class os {
       set gfxpayload=$linux_gfx_mode
       insmod part_msdos
       insmod ntfs
       set root='(hd0,msdos2)'
       search --no-floppy --fs-uuid --set=root 9A200E69200E4CA7
       loopback loop0 /ubuntu/disks/root.disk
       set root=(loop0)
       linux /boot/vmlinuz-3.2.0-rc7+ root=UUID=9A200E69200E4CA7
loop=/ubuntu/disks/root.disk ro quiet splash vt.handoff=7
       initrd /boot/initrd.img-3.2.0-rc7+
}
menuentry 'Ubuntu, with Linux 3.2.0-rc7+ (recovery mode)' --class
ubuntu --class gnu-linux --class gnu --class os {
       set gfxpayload=$linux_gfx_mode
       insmod part_msdos
       insmod ntfs
       set root='(hd0,msdos2)'
       search --no-floppy --fs-uuid --set=root 9A200E69200E4CA7
       loopback loop0 /ubuntu/disks/root.disk
       set root=(loop0)
       echo 'Loading Linux 3.2.0-rc7+ ...'
       linux /boot/vmlinuz-3.2.0-rc7+ root=UUID=9A200E69200E4CA7
loop=/ubuntu/disks/root.disk ro recovery nomodeset
       echo 'Loading initial ramdisk ...'
       initrd /boot/initrd.img-3.2.0-rc7+
}
menuentry 'Ubuntu, with Linux 3.2.0-rc7+.old' --class ubuntu --class
gnu-linux --class gnu --class os {
       set gfxpayload=$linux_gfx_mode
       insmod part_msdos
       insmod ntfs
       set root='(hd0,msdos2)'
       search --no-floppy --fs-uuid --set=root 9A200E69200E4CA7
       loopback loop0 /ubuntu/disks/root.disk
       set root=(loop0)
       linux /boot/vmlinuz-3.2.0-rc7+.old root=UUID=9A200E69200E4CA7
loop=/ubuntu/disks/root.disk ro quiet splash vt.handoff=7
       initrd /boot/initrd.img-3.2.0-rc7+
}
menuentry 'Ubuntu, with Linux 3.2.0-rc7+.old (recovery mode)' --class
ubuntu --class gnu-linux --class gnu --class os {
       set gfxpayload=$linux_gfx_mode
       insmod part_msdos
       insmod ntfs
       set root='(hd0,msdos2)'
       search --no-floppy --fs-uuid --set=root 9A200E69200E4CA7
       loopback loop0 /ubuntu/disks/root.disk
       set root=(loop0)
       echo 'Loading Linux 3.2.0-rc7+.old ...'
       linux /boot/vmlinuz-3.2.0-rc7+.old root=UUID=9A200E69200E4CA7
loop=/ubuntu/disks/root.disk ro recovery nomodeset
       echo 'Loading initial ramdisk ...'
       initrd /boot/initrd.img-3.2.0-rc7+
}
}
### END /etc/grub.d/10_lupin ###

### BEGIN /etc/grub.d/20_linux_xen ###
### END /etc/grub.d/20_linux_xen ###

### BEGIN /etc/grub.d/20_memtest86+ ###
### END /etc/grub.d/20_memtest86+ ###

### BEGIN /etc/grub.d/30_os-prober ###
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries. Simply type the
# menu entries you want to add after this comment. Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###

### BEGIN /etc/grub.d/41_custom ###
if [ -f $prefix/custom.cfg ]; then
 source $prefix/custom.cfg;
fi
### END /etc/grub.d/41_custom ###
--------------------------------------------------------------------------------

============================= sda2/Wubi/etc/fstab: =============================

--------------------------------------------------------------------------------
# UNCONFIGURED FSTAB FOR BASE SYSTEM
/host/ubuntu/disks/swap.disk none swap sw 0 0
--------------------------------------------------------------------------------

================= sda2/Wubi: Location of files loaded by Grub: =================

          GiB - GB File Fragment(s)

  1.301773071 = 1.397768192 boot/grub/grub.cfg 2
 13.741065025 = 14.754356224 boot/initrd.img-3.2.0-6-generic 62
 13.749551773 = 14.763468800 boot/initrd.img-3.2.0-7-generic 63
  1.417470932 = 1.521997824 boot/initrd.img-3.2.0-rc7+ 22
  2.067645073 = 2.220116992 boot/vmlinuz-3.2.0-6-generic 94
 13.718629837 = 14.730266624 boot/vmlinuz-3.2.0-7-generic 24
  1.418664932 = 1.523279872 boot/vmlinuz-3.2.0-rc7+ 30
  1.388851166 = 1.491267584 boot/vmlinuz-3.2.0-rc7+.old 31
 13.749551773 = 14.763468800 initrd.img 63
 13.741065025 = 14.754356224 initrd.img.old 62
 13.718629837 = 14.730266624 vmlinuz 24
  2.067645073 = 2.220116992 vmlinuz.old 94

fdisk:
Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders, total 976773168 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x8ea8e911

  Device Boot Start End Blocks Id System
/dev/sda1 * 2048 206847 102400 7 HPFS/NTFS/exFAT
/dev/sda2 206848 976771071 488282112 7 HPFS/NTFS/exFAT

mount:
/dev/loop0 on / type ext3 (rw,commit=0,commit=0)
proc on /proc type proc (rw,noexec,nosuid,nodev)
sysfs on /sys type sysfs (rw,noexec,nosuid,nodev)
none on /sys/fs/fuse/connections type fusectl (rw)
none on /sys/kernel/debug type debugfs (rw)
none on /sys/kernel/security type securityfs (rw)
udev on /dev type devtmpfs (rw,mode=0755)
devpts on /dev/pts type devpts (rw,noexec,nosuid,gid=5,mode=0620)
tmpfs on /run type tmpfs (rw,noexec,nosuid,size=10%,mode=0755)
none on /run/lock type tmpfs (rw,noexec,nosuid,nodev,size=5242880)
none on /run/shm type tmpfs (rw,nosuid,nodev)
/dev/sda2 on /host type fuseblk
(rw,nosuid,nodev,relatime,user_id=0,group_id=0,allow_other,blksize=4096)
binfmt_misc on /proc/sys/fs/binfmt_misc type binfmt_misc
(rw,noexec,nosuid,nodev)
gvfs-fuse-daemon on /home/miles/.gvfs type fuse.gvfs-fuse-daemon
(rw,nosuid,nodev,user=miles)

[Miles Lane (miles-lane)]

I have reported this on the Grub2 support mailing list and on the Linux Kernel mailing list. So far, no responses. Can someone here give me some next steps in trying to track down the problem?

[Miles Lane (miles-lane)]

Is anybody home?

[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.]