Ubuntu Server 11.04 Halts when issues “reboot” command

The Node Controller I built in an earlier post consistently experienced this system halt issue. Basically, after I entered a “reboot” command. the system halted with a “shutting down” message showing on the screen (forever).

The hardware is Dell Optiplex 745 and the operating system was Ubuntu 11.04 (server).

root@ubuntu-NodeController:~# uname -a

Linux ubuntu-NodeController 2.6.38-13-generic-pae #53-Ubuntu SMP Mon Nov 28 19:41:58 UTC 2011 i686 i686 i386 GNU/Linux

I did some search online and found the issue was caused by a Ubuntu 11.04 software bug

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/255961

So I upgraded the Ubuntu software release:

# sudo apt-get install update-manager-core

# sudo do-release-upgrade

Now the system is running on Ubuntu 11.10 server and the issue is resolved.

root@ubuntu-NodeController:~# uname -a

Linux ubuntu-NodeController 3.0.0-14-generic-pae #23-Ubuntu SMP Mon Nov 21 22:07:10 UTC 2011 i686 i686 i386 GNU/Linux

P.S. while searching for the solution, I stumble upon a post suggesting to set the “reboot” option to one of these “bios”, “apci” and “force” (in the kernel). 

# vi /etc/default/grub

GRUB_CMDLINE_LINUX="reboot=x"

# update-grub

While the suggestion was not helpful to my setup, it could be useful for other cases of system restart halt where OS upgrade is not an option.