Try to rmmod all modules and see whether reboot works, if it is try to
unload only half of them, etc... (And tell us which module blocks your reboot)
If it will be hard to reproduce or procedure above won't work, please
enable "Kernel debugging" (CONFIG_DEBUG_KERNEL), "Driver Core verbose
debug messages" (CONFIG_DEBUG_DRIVER) and copy messages from dmesg which
happen before oops.
I managed to reproduce the problem. But it is not "exact science".
What I did was:
- boot RIPLinux 6.3 USB stick
- in boot menu select first option (boot 32 bit kernel)
- when asked opt for keyboard selection
- select "Slovene"
- login as root on VT1
- enter startx
- in X right click and select XTerm in menu
- in same menu select Setup/<fist option> (for wired network)
- wait for the DHCP dialog to appear and click OK
- from right click menu select Firefox/Start
- ctrl-alt-f2 to VT2
- login as root
- enter: reboot -f
It gives the oops in 75% of cases.
The steps above do not load any modules that are not loaded by default anyway.
I attach the full dmesg output.