Comment 15 for bug 364524

To add some more information: when the system freezes, the mousepointer will move freely, but there's no interaction with anything. The pointer isn't visible when moving it across gnome-terminal. Alt-SysRq-REISUB and Ctrl-alt-backspace work fine to reset things. I can also ssh into the box from another pc, and kill gnome-terminal to restore all functionality to the desktop.
This is true for both an ati system (radeon or radeonhd driver) and an nvidia one (propietary nvidia or nouveau driver). Compiz is disabled.

I also tried to get a backtrace on Xorg, but don't know if it was a success. At the start of the backtrace there's a lot of single-stepping (because when using 'cont' instead of 'step' gdb would just sit there doing nothing).

uname -a:
Linux jaunty-desktop 2.6.28-11-generic #42-Ubuntu SMP Fri Apr 17 01:57:59 UTC 2009 i686 GNU/Linux