Re: Strange kernel boot hang

["Douglas A. Tutty" <dtutty@porchlight.ca>]

On Tue, Dec 18, 2007 at 03:04:23PM +0000, Matt Baker wrote:
> 
> I've been having a nightmare with a box that after a kernel update
> refuses to boot. Below is a transcript of what I've tried.
> -
> 
> Server is a Dell PowerEdge 2800 with 6Gb Ram, LSI Logic Perc 4e/DC RAID
> controller.
 
> By mounting the filesystems and chrooting into the debian personality to
> access the system. Like so:
> 
> modprobe dm-mod
> vgscan
> vgchange -a y
> mount /dev/sda3 /mnt/gentoo
> cd !$
> mount /dev/sda1 boot/
> for x in usr home var ;do mount /dev/mapper/vg1-$x $x;done
> mount -t proc proc proc/
> mount -o bind /dev dev/
> chroot . /bin/bash
> 

It appears that you are using LVM for /usr, /home, and /var.  To
eliminate LVM problems, try booting with init=/bin/sh.  This should
remove any need for those partitions and allow you to focus on getting
the kernel to boot.
 -
> Rebooted with the floppy and get a grub menu.
> Manually typing the kernel boot params into grub:
> 
> root (hd0,0)
> kernel (hd0,0)/vmlinuz ro root=/dev/sda3 console=/dev/tty0
> initrd (hd0,0)/initrd.gz
> boot

which would change your kernel command line to:

kernel (hd0,0)/vmlinuz ro root=/dev/sda3 init=/bin/sh

I don't know that you need the console= line unless you're using a
non-standard console.


I've lost what you've tried when and in what order, so I appologize if
you've already tried this:

Ensure that when you boot, you get the grub menu.  If you don't, then
grub can't see the /boot directory/partition.  If it can't see it, it
can't load the kernel from it.  If you need to, install grub, then run
dpkg-reconfigure [the kernel package] to get the grub menu built
correctly and rebuild the initrd.  

Then manually edit /boot/grub/menu.list so that you automatically get an
entry for the standard kernel with init=/bin/sh.  After the edit, re-run
update-grub to get it to regenerate menu.list.

Once you get grub itself working, you can work on getting the kernel to
boot with init=/bin/sh.  What is the error you get from the kernel?  Can
it find the root partition?  

Doug.