i have the same problem
i exprrience X freezing a lot, often when pushing it under some load (opening 
windows quickly) and often when i drag images around in gqview.
It freezes and X uses 100% cpu power.

Problem happend quite often.

(In reply to comment #0)

> I've had X freezing every few hours or so, often when selecting a region of 
the
> screen (using ksnapshot).
> Reported on fedora bugzilla:
> https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=120018
> (using their xorg-x11-0.6.6-0.2004_03_30.1)
> but reproducing here in case it is a relevant problem.
> The applications are still running (but the local keyboard becomes 
disfunctional
> until X is killed - curiously the mouse cursor still moves around the screen),
> and so I can ssh in and get a backtrace from gdb:
> #0  0x08b257d1 in ?? ()
> #1  0x08b2620d in ?? ()
> #2  0x08ba5856 in ?? ()
> #3  0x08ba5291 in ?? ()
> #4  0x08ba6502 in ?? ()
> #5  0x08ba5103 in ?? ()
> #6  0x0817231a in miFillUniqueSpanGroup ()
> #7  0x0816fcf4 in miCleanupSpanData ()
> #8  0x0817149a in miWideDash ()
> #9  0x0816ba27 in miPolyRectangle ()
> #10 0x0819638c in miSpritePolyRectangle ()
> #11 0x080be6b3 in ProcPolyRectangle ()
> #12 0x080bb5d2 in Dispatch ()
> #13 0x080ce36c in main ()
> #14 0x00b01eb3 in __libc_start_main () from /lib/tls/libc.so.6

What graphcis hardware are you using (both of you)?

(In reply to comment #2)
> What graphcis hardware are you using (both of you)?

I have seen a lot of reports about both Ati and Nvidia cards, etc...
The problem was reported in various distributions, with various kernel versions,
various hardware. Since the crashes are reported on XFree aswell, my personal
guess is that its a long-lurking bug which got carried over to the Xorg source.

This url below contains lots of reports on various systems and guesses. Since
the only common thing in all reports is X (high cpu load, mouse strangely
working, keyboard not) i think its fairly accurate to think the bug is in Xorg.
Aswell, here is a short (incomplete) summary of this all:
- The crash occurs on various hardware
-- CPU: P4 3Ghz, AMD Athlon Thunderbird 1400, AMD Athlon 900Mhz, Athlon XP
1500+, Pentium III 866MHz
-- GFX cards: Radeon 9200, NVidia GeForce2 GTS/Pro, GeForce Ultra 5700
-- M/B: TODO
-- Mem: various sizes

- It occurs on various w/ms like: kde, gnome, ion2, fluxbox

- It occurs on various kernel versions: 2.4.23-ck1 - 2.6.9-rc2 (gentoo patched)

- It occurs on various X versions:
--XFree(TODO: accurate version)
--Xorg up to 6.7.0-rc2
--Xorg up to 6.8.0-rc1 (a strange line is reported on crash)

-Reported with the following applications(usually when heavy mouse activity
occurs), mostly GTK apps: browsers(firefox,konqueror,galleon,Opera), gaim, gkrellm

-Reports in various distributions: debian, mandrake, fedora and gentoo
Sympthoms:

- X CPU usage 100%
- Keyboard is not working
- Mouse is working but nothing is clickable (in some cases mouse is not working
any more)
- Magic SysRq is possible

My story:

CPU: Intel P4 3Ghz
MB: SIS
RAM: 512MB
GFX: ATi Radeon 9200
HDD: 80Gb

The system is brand new. I installed gentoo from stage1 this week(2004.11.03).
CFLAGS="-march=pentium4 -O3 -pipe"
Im using Xorg 6.7.0-rc2. I usually crash when typeing posts like this in firefox
and (maybe irrelevant crash here) when trying to run scorched3d with HW
mip-mapping(this last one is 100% reproducable crash for me).


Finally, here is the url: http://forums.gentoo.org/viewtopic.php?p=1726404

Are any of you overclocking your CPUs? What types of mice - serial, PS/2, USB? 
 
There are likely multiple different ways to trigger this behavior, and so 
there won't be just one fix for it - if you can reliably trigger it somehow, 
backtraces would be very helpful. 

I'm closing this bug due to the lack of activity. If problem still exists please
reopen.