Panic when doing shutdown or reboot

[William Perkins]

I have two systems with which I am having problems during a shutdown or 
reboot.  Both are x86_64 systems running Fedora-18 (Spherical Cow).  In 
both cases the systems will panic before the shutdown or reboot process 
is completed and system restarts or powers off.  This is a problem because 
the system that controls the UPS must poweroff to shutdown the UPS during 
a power failure.  If it does not, the UPS powers off after the batteries 
run down.  This is not good for the UPS.

Anyway, this problem will occurs on either of these systems after some 
time has been spent working on them: running X, Firefox, Liferea, LibreOffice,
etc...  If you than shutdown apps, close windows and terminate the window 
manager (FVWM), and than do a shutdown or reboot from the command line.
the system will panic before the shutdown/reboot is done with the 
following sampled lines:

Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000100
Pid: 1, comm: shutdown Not tainted 3.7.9-205.fc18.x86_64 #1

I am now running the latest kernel: 3.8.1-201.fc18.x86_64 and application 
updates, but that has not changed the conditions of this problem.  I am 
looking for hints for where the source of the problem may lie.  I have 
tried the Mate and XFCE desktops, and have not seen the problem with 
them, but I have not used either of them very extensively.  I have 
searched Bugzilla for similar descriptions with no success.  The problem 
appears to be a user level issue that is causing the kernel panic.  Not 
something that I would expect to happen.

Bill