Comment 23 for bug 723482

Here is the technique I use to work around the problem, it might not be any better than Sebastian's technique, but anyway here it is, in the hope it might help Herbert:
 - on grub screen, hit 'e' to edit boot commands
 - add init=/bin/bash to the kernel command line
 - press F10 to boot the kernel
 -at the prompt, type the following
    getty -8 -n -l /bin/bash 38400 tty2 &
    getty -8 -n -l /bin/bash 38400 tty3 &
and make sure with Ctl-Alt-F2 and Ctrl-Alt-F3 that you can switch terminal
 - type the following to resume the init sequence:
    exec init
 - switch terminal, get the process number of mountall with
     ps aux
then kill -9 <process number>
 - switch terminal again, and type
   mountall
to restart it. After a while, stop it with Ctl-C, then restart it again, At my place, it starts booting normally at this point.

For your kernel version being outdated in your natty alpha release, you should probably try using "aptitude dist-upgrade" instead of "aptitude clean-upgrade" once you succeeded to boot (just a guess, I'm not sure). I do not have "crashkernel" option either on my grub command line. I don't think the kernel version or having room reserved for a crash kernel matters at all for the mountall problem, anyway.

I hope that helps.