howto debug X crash from kdm shutdown?
 

I started having X crash on shutdown, when shutting down via the kdm screen; if I exit the kdm login screen and use ctrl-alt F2 to get a console, log in as root and do "shutdown -h now" from there, it doesn't crash. Some time ago, I had this start happening on a now defunct box (same linux version) and updating X a bit cured it. On the current box, the trouble started after updating to the same version that cured it before, following a re-install plus various updates.

I'm using RedHat 6.1 on an Intel P233, kernel 2.2.24 (compiled from kernel.org source), the original XFree86 version was 3.3.5-3, and the update was to 3.3.6-29.

The main error message I get is this (had to hand copy from the screen):

Caught signal 11

Server aborting...
Warning: /dev/mouse unable to get status of mouse fd (input/output error)

followed by a lot of trace info, too much to hand copy, plus a direction to do:

gdb /etc/X11/X //core

for debugging, which only produces:

GNU gdb 4.18
Copyright 1998 Free Software Foundation, Inc.
(no debugging symbols found)...
<snip license stuff>
//core: No such file or directory.
(gdb)

Can anyone suggest whats happening or how to troubleshoot what's going on here?

Thanks in advance,

John