Help with debuging Xserver / Goes in an infinite loop / No error messages

[Joshua C.]

I have a problem with my xorg-x11-server-Xorg-1.6.4-0.1.fc11.x86_64. I
read the instructions here
http://www.x.org/wiki/Development/Documentation/ServerDebugging but
this didin't help. My Xserver goes in an infinite loop and starts
consuming 100% my cpu. Therefore the whole system freezes and I have
to manually reboot it. This happens all the time when I use firefox on
random sites. After restart there is nothing in the xorg.0.log and
everything repeats itself when I start firefox again. Therefore I need
to remove the savesession.js from the firefox home directory.

On the second mashine (with gdb) I also turned this on: handle SIGUSR1
nostop, handle SIGUSR2 nostop, handle SIGPIPE nostop.

The Xserver just keeps running and I get no error messages on the
second mashine.

Only once I got the following in dmesg (repeating many times)
[drm:drm_buffer_object_validate] *ERROR* Out of aperture space or DRM
memory quota.
[drm:drm_buffer_object_validate] *ERROR* Failed moving buffer.
ffff880142183000 19219 20000a7 10000a7
[drm:drm_buffer_object_validate] *ERROR* Out of aperture space or DRM
memory quota.
[drm:drm_buffer_object_validate] *ERROR* Failed moving buffer.
ffff880142183000 19219 20000a7 10000a7
[drm:drm_buffer_object_validate] *ERROR* Out of aperture space or DRM
memory quota.

The Xorg.0.log also looks normal. Some weeks ago I got this in it (just once):
(EE) RADEON(0): ADVANCE_RING count != expected (14 vs 16) at
radeon_textured_videofuncs.c:1623
(EE) RADEON(0): ADVANCE_RING count != expected (14 vs 16) at
radeon_textured_videofuncs.c:1623
(EE) RADEON(0): ADVANCE_RING count != expected (14 vs 16) at
radeon_textured_videofuncs.c:1623

Installed are:
kernel-debuginfo-2.6.30.8-64.fc11.x86_64
kernel-debuginfo-common-x86_64-2.6.30.8-64.fc11.x86_64
kernel-2.6.30.8-64.fc11.x86_64

xorg-x11-server-utils-7.4-7.1.fc11.x86_64
xorg-x11-server-common-1.6.4-0.1.fc11.x86_64
xorg-x11-server-Xorg-1.6.4-0.1.fc11.x86_64
xorg-x11-server-debuginfo-1.6.4-0.1.fc11.x86_64

xorg-x11-drv-ati-debuginfo-6.12.2-18.fc11.x86_64
xorg-x11-drv-ati-6.12.2-18.fc11.x86_64

mesa-dri-drivers-7.6-0.2.fc11.x86_64
mesa-libGLU-7.6-0.2.fc11.x86_64
mesa-libGL-7.6-0.2.fc11.x86_64
mesa-debuginfo-7.6-0.1.fc11.x86_64

libdrm-debuginfo-2.4.11-2.fc11.x86_64
libdrm-2.4.11-2.fc11.x86_64

I'd like to file a bug report about this but there's not many
information I can provide. How to debug it or to make it print
something more useful on my second mashine?