Created attachment 38448 [details]
snippet from gdb session
I have xorg-server 1.8.2 with radeon driver from xf86-video-ati 6.13.1.
Mesa version is 7.8.2.
FreeBSD DRI doesn't support DRI2, so DRI is used.
X server reproducibly crashes when I repeatedly minimize and restore a window by pressing its icon on a taskbar in KDE4 with OpenGL effects enabled.
I am attaching a snippet from gdb debugging session.
Please let me know if you would like any additional information or testing.
*** This bug has been marked as a duplicate of bug 28181 ***
Couple of details: glxPriv->pDraw is not NULL but gdb says that it points to inaccessible memory.