On an HP XM3 running RH 7.0 (with all published patches applied) generates 
a seg fault at shutdown.  Does not appear to be a pressing problem, as 
system comes back up with clean file systems.  After final message "System 
halted" the following is the seg fault info which comes up (this PC has 
a "Smart Switch" which may not be properly responding to the operating 
system's attempt to do a "soft switch" shutdown, though not sure if a 
malfunctioning "Smart switch" would be severe enough to cause this seg 
fault, or if that's what's actually happening here):

Code <1> Unable to handle kernel NULL pointer dereference at virtual 
address 0000011c

Current-> tss.cr3=03a1a000, %cr3=03a1a000
*pde=00000000
oops: 0000
eip: 0010 [<c010a40d>]
eflags: 00010046
Process halt (pid:1053, process nr: 16, stackpage=c2abdd000)

/etc/rc0.d/S01halt: line 1: 1053 Segmentation Fault  halt -i -d -p

Command being used is:  shutdown -h now