Comment 9 for bug 522197

jordanwb, Thank you for your prompt reply!

I am sure it's not kernel panic,because I am on x86 but didnt not see any oops message and call stack.

I am sure kernel finished loading and initramfs is finished because I already saw udev warnings pulse a fsck output like
sda1 xxxxxx/xxxxx blocks.

if you keep /etc/ureadahead.conf as default
like
normal exit 0

then I will see the "init: ureadahead PID terminated with status 4", sth similar to this

then I modify /etc/ureadahead.conf by live CD to
normal exit 0 4
(added 4 as the normal exit status if I understand it right)

and the "terminated with status 4" message is gone, and the last message is the "XXXX blocks " one

another thing make me believe it is NOT kernel panic is
while I was sending ALT+DEL+CTRL for rebooting , the system respones with the menu looks like

continue normal booting
ctrl+D for a maitainance shell
....some other options......

but before you can make a choice, the system reboots.

So ,I dont know what exactly blocks the system(or the init process) from booting. init in upstart? ureadahead?usplash?GDM?I am using
recovery option in grub with "single" as the kernel option, should go into rc1.S which is not related to GDM. right?
all the above are reported from a 2.6.32-18-generic kernel

I tried to remove ureadahead but found ubuntu-minimal depends on it, if I proceed, I probably will remove all the system?

I tried to delete the config files in /etc/ureadahead/*,
the same.