xserver 1.6
kernel 2.6.29rc8
radeon drm drom airlied drm-next

01:00.0 VGA compatible controller: ATI Technologies Inc Mobility Radeon HD 3400 Series

When logging out from kdm (kde4) then X segfaults. This only happens if DRI is enabled. There is no such problem with DRI disabled.

I also have second laptop with x600 card (r300) with more or less the same software (the same packages/distro), but i686 this time and the problem doesn't occur there even with DRI.

Looks like some DRI problem in r600 driver.

Backtrace:
0: /usr/bin/X(xorg_backtrace+0x26) [0x4e9e76]
1: /usr/bin/X(xf86SigHandler+0x39) [0x48c9e9]
2: /lib64/libc.so.6 [0x7f67b76a3550]
3: /usr/bin/X [0x509976]
4: /usr/lib64/xorg/modules/extensions//libdbe.so [0x7f67b6593268]
5: /usr/bin/X(compPositionWindow+0x73) [0x4faac3]
6: /usr/bin/X(InitRootWindow+0x2d) [0x43293d]
7: /usr/bin/X(main+0x358) [0x42d618]
8: /lib64/libc.so.6(__libc_start_main+0xe6) [0x7f67b768f5b6]
9: /usr/bin/X [0x42cb19]

pPixmap is 0x0

Program received signal SIGSEGV, Segmentation fault.
ShmDestroyPixmap (pPixmap=0x0) at shm.c:285
285         if (pPixmap->refcnt == 1)
(gdb) bt
#0  ShmDestroyPixmap (pPixmap=0x0) at shm.c:285
#1  0x00007f1d748982c8 in miDbePositionWindow (pWin=0xd82040, x=<value optimized out>, y=<value optimized out>) at midbe.c:728
#2  0x00000000004faae3 in compPositionWindow (pWin=<value optimized out>, x=0, y=0) at compwindow.c:224
#3  0x000000000043295d in InitRootWindow (pWin=0xd82040) at window.c:477
#4  0x000000000042d638 in main (argc=7, argv=0x7fff7f9f5738, envp=<value optimized out>) at main.c:365
(gdb) l
280     static Bool
281     ShmDestroyPixmap (PixmapPtr pPixmap)
282     {
283         ScreenPtr       pScreen = pPixmap->drawable.pScreen;
284         Bool            ret;
285         if (pPixmap->refcnt == 1)
286         {
287             ShmDescPtr  shmdesc;
288             shmdesc = (ShmDescPtr)dixLookupPrivate(&pPixmap->devPrivates,
289                                                    shmPixmapPrivate);
(gdb)