Compiz doesn't crash so there's no backtrace for compiz.
The X server freeze but doesn't crash. I reproduced the problem with xserver-xorg-dbg installed and attached Xorg.0.log.
When the X server freeze, it's still possible to move the mouse and it's still possible to press CTRL+ALT+PrntScreen and CTRL+ALT+F6 to switch on a tty console.
It happens on :
01:00.0 VGA compatible controller [0300]: nVidia Corporation GeForce 8300 GS [10de:0423] (rev a1)
Section "Device"
Identifier "nVidia Corporation G80 [GeForce 8300 GS]"
Driver "nvidia"
Busid "PCI:1:0:0"
Option "AddARGBVisuals" "True"
Option "AddARGBGLXVisuals" "True"
Option "NoLogo" "True"
EndSection
compiz : 1:0.6.2+ git20071119- 0ubuntu1~ gutsy1
xserver-xorg : 1:7.2-5ubuntu13
Compiz doesn't crash so there's no backtrace for compiz.
The X server freeze but doesn't crash. I reproduced the problem with xserver-xorg-dbg installed and attached Xorg.0.log.
When the X server freeze, it's still possible to move the mouse and it's still possible to press CTRL+ALT+PrntScreen and CTRL+ALT+F6 to switch on a tty console.