LinuxQuestions.org - [SOLVED] Slackware64 13.37 KVM GUEST Xorg segfaults when starting KDE (workaround)

Installed Slackware64 on a KVM Guest with Virt-Manager in Fedora 15 beta and
found that Xorg crashes (segfaults) when loading KDE.
XFCE, Blackbox both works ok, even KDM (while in RL4) works ok.

sha256sum of the iso: 382064d41b1f13b8ebf1399aed73606fe23c46dd3b8d110e403aacd5ae8f97af

Host: F15-beta KDE x86_64, AMD Phenom II
Guest: Slackware64 13.37

Issue:
* Xorg segfaults when loading KDE, XFCE works ok.
* In RL3, startx fails.
* In RL4, KDM loads but KDE fails when loading, after log-in.

Woraround:
* In RL4, KDM: Select KDE Failsafe, it works. (Normal KDE does not).
Sadly i do not know how to invoke it manually from RL3, so
startx will not work.

Virtualization: KVM, Virt-Manager
Guest HW: VGA Cirrus or VMVGA, both affected.
Guest Machine Type: Linux, Other 2.6.X Kernel.

Typical backtrace:

Backtrace:
[ 433.802] 0: /usr/bin/X (xorg_backtrace+0x28) [0x4a02d8]
[ 433.802] 1: /usr/bin/X (0x400000+0x60fc9) [0x460fc9]
[ 433.802] 2: /lib64/libc.so.6 (0x7f81e373d000+0x340b0) [0x7f81e37710b0]
[ 433.802] 3: /lib64/libc.so.6 (0x7f81e373d000+0x8b04b) [0x7f81e37c804b]
[ 433.802] 4: /usr/lib64/xorg/modules/libfb.so (fbBlt+0xf8) [0x7f81e180e2b8]
[ 433.802] 5: /usr/lib64/xorg/modules/libfb.so (fbBltStip+0x40) [0x7f81e180f040]
[ 433.802] 6: /usr/lib64/xorg/modules/libfb.so (fbGetImage+0x206) [0x7f81e18147a6]
[ 433.802] 7: /usr/lib64/xorg/modules/libxaa.so (0x7f81e1592000+0x93fd) [0x7f81e159b3fd]
[ 433.802] 8: /usr/lib64/xorg/modules/libxaa.so (0x7f81e1592000+0x5a890) [0x7f81e15ec890]
[ 433.802] 9: /usr/bin/X (0x400000+0x154e48) [0x554e48]
[ 433.802] 10: /usr/lib64/xorg/modules/extensions/libglx.so (0x7f81e2c80000+0x38e4a) [0x7f81e2cb8e4a]
[ 433.802] 11: /usr/lib64/xorg/modules/dri/swrast_dri.so (0x7f81e0c9a000+0x28a7b) [0x7f81e0cc2a7b]
[ 433.802] 12: /usr/lib64/xorg/modules/extensions/libglx.so (0x7f81e2c80000+0x38de8) [0x7f81e2cb8de8]
[ 433.802] 13: /usr/lib64/xorg/modules/extensions/libglx.so (0x7f81e2c80000+0x35a0e) [0x7f81e2cb5a0e]
[ 433.802] 14: /usr/lib64/xorg/modules/extensions/libglx.so (0x7f81e2c80000+0x36852) [0x7f81e2cb6852]
[ 433.802] 15: /usr/lib64/xorg/modules/extensions/libglx.so (0x7f81e2c80000+0x38463) [0x7f81e2cb8463]
[ 433.802] 16: /usr/bin/X (0x400000+0x2def1) [0x42def1]
[ 433.802] 17: /usr/bin/X (0x400000+0x21ffe) [0x421ffe]
[ 433.802] 18: /lib64/libc.so.6 (__libc_start_main+0xfd) [0x7f81e375be5d]
[ 433.802] 19: /usr/bin/X (0x400000+0x21bb9) [0x421bb9]
[ 433.802] Segmentation fault at address (nil)
[ 433.802]
Fatal server error:
[ 433.802] Caught signal 11 (Segmentation fault). Server aborting
[ 433.802]
[ 433.802]
Please consult the The X.Org Foundation support
at http://wiki.x.org
for help.