Kernel panic -- Not syncing | VFS: Unable to mount root fs

Charles Turner lookatmymanbreasts at
Sun Apr 5 15:17:16 PDT 2009

My disk overview is as follows:

sda:  /dev/sda1 : GNU/Linux
        /dev/sda2: SWAP
sdb: /dev/sdb1: Backup space
        /dev/sdb2: Extended
        /dev/sdb5: SWAP
        /dev/sdb6: LFS 6.4 root partition (reiserfs)

My menu.lst is as follows:


# The first entry is for LFS.
title LFS 6.4
root (hd1,5)
kernel /boot/ckernel- root=/dev/sdb6

I have installed GRUB on both disks, sda and sdb.

from chroot environment in LFS 6.4:
root:/boot/grub# ls
menu.lst  menu.lst~  reiserfs_stage1_5	stage1  stage1 stage2

I have reiserfs support compiled into my kernel:


I saw sata messages scrolling by in the kernel messages before the
panic, I couldn't scroll up in the console to
make a note of them though. I assume that I have the appropriate
support in my kernel for sata. I also have support
for the Intel ICH controller.

When i boot with these settings GRUB initially tells me that there is
no such partition hd1,5. If i change this to hd0,5,
it boots. I assume my BIOS changes the drive ordering when I select
sdb from the boot select menu.

The kernel soon tells me this:

VFS: cannot open root device "sdb6" or unknown-block (8,6)

Please append correct root= boot option: here are the available partitions

[3.515198] 0800 488386584   sda   driver: sd
[3.515277] 0810 488386584   sdb   driver: sd
[3.515356] 0b00 1048575       sr0   driver: sr
[3.515434] Kernel panic -- not syncing: VFS: unable to mount root fs
on unknown-block (8,6)

I've tried changing the root= boot option to /dev/sda6 thinking that
with the drives swapping their names it would work
but it doesn't.

Any pointers appreciated. I don't know what to investigate now.

Thanks for your time.

Charlie Turner

More information about the lfs-support mailing list