I use KDE 4...

Sounds suicidal? Go check your facts. Anyway, I use Mesa 7.7 for 3D, plus libdrm and the X.org radeon driver from their git repositories. The system is Debian Squeeze, but it's a few weeks behind testing because I've not had access to a strong connection to download the shitload of packages (~350 MB) for upgrading.

I normally use the QtCurve style for Qt3, Qt4 and Gtk2 applications, but last night I decided to give Nitrogen-style (based on Oxygen) a go again.

I found that if I open Konqueror's bookmarks menu, when it has many more elements than they fit in the whole screen, X.org crashes!

Backtrace:
0: /usr/bin/X(xorg_backtrace+0x26) [0x4ee056]
1: /usr/bin/X(xf86SigHandler+0x39) [0x484199]
2: /lib/libc.so.6 [0x7ffc172e8fd0]
3: /usr/lib/dri/r600_dri.so(r600SetTexOffset+0x8b) [0x7ffc028e306b]
4: /usr/lib/xorg/modules/extensions//libglx.so [0x7ffc163b911c]
5: /usr/lib/xorg/modules/extensions//libglx.so(__glXleaveServer+0x18) [0x7ffc163affa8]
6: /usr/lib/xorg/modules/extensions//libglx.so [0x7ffc163b055f]
7: /usr/bin/X(Dispatch+0x374) [0x44d494]
8: /usr/bin/X(main+0x3aa) [0x43337a]
9: /lib/libc.so.6(__libc_start_main+0xfd) [0x7ffc172d5abd]
10: /usr/bin/X [0x432819]

Fatal server error:
Caught signal 11.  Server aborting

It reproduces with the Oxygen theme too. All with KDE 4.3.2 — but the crash seems to come via Mesa 7.7's ATI R6xx/R7xx DRI driver. Ah, yays for newborn drivers.