Mostly, when I scroll a HTML e-mail within Kontact my system crashes. The desktop becomes unresponsive. However, I can still move the mouse, but not click, and I can login via SSH and reboot the system.

Dmesg:

[ 4323.214686] nouveau 0000:01:00.0: kontact[19175]: Unknown handle 0x00000039
[ 4323.214694] nouveau 0000:01:00.0: kontact[19175]: validate_init
[ 4323.214698] nouveau 0000:01:00.0: kontact[19175]: validate: -2
[ 4323.230994] nouveau 0000:01:00.0: kontact[19175]: Unknown handle 0x00000039
[ 4323.231002] nouveau 0000:01:00.0: kontact[19175]: validate_init
[ 4323.231006] nouveau 0000:01:00.0: kontact[19175]: validate: -2
[ 9642.309946] nouveau 0000:01:00.0: kontact[19175]: Unknown handle 0x0000001a
[ 9642.309950] nouveau 0000:01:00.0: kontact[19175]: validate_init
[ 9642.309952] nouveau 0000:01:00.0: kontact[19175]: validate: -2
[ 9654.499185] nouveau 0000:01:00.0: kontact[19175]: Unknown handle 0x0000005e
[ 9654.499191] nouveau 0000:01:00.0: kontact[19175]: validate_init
[ 9654.499193] nouveau 0000:01:00.0: kontact[19175]: validate: -2
[ 9655.527534] nouveau 0000:01:00.0: kontact[19175]: Unknown handle 0x0000003c
[ 9655.527542] nouveau 0000:01:00.0: kontact[19175]: validate_init
[ 9655.527546] nouveau 0000:01:00.0: kontact[19175]: validate: -2
[ 9655.534613] nouveau 0000:01:00.0: gr: DATA_ERROR 0000000c [INVALID_BITFIELD] ch 21 [023e9d4000 kontact[19175]] subc 0 class a097 mthd 2384 data 20050004
[ 9655.537255] nouveau 0000:01:00.0: kontact[19175]: Unknown handle 0x0000003c
[ 9655.537261] nouveau 0000:01:00.0: kontact[19175]: validate_init
[ 9655.537264] nouveau 0000:01:00.0: kontact[19175]: validate: -2
[ 9655.537530] nouveau 0000:01:00.0: fifo: read fault at 0000000000 engine 00 [GR] client 14 [SCC] reason 02 [PTE] on channel 21 [023e9d4000 kontact[19175]]
[ 9655.537538] nouveau 0000:01:00.0: fifo: gr engine fault on channel 21, recovering...

Xorg.0.log:

(EE) [mi] EQ overflowing.  Additional events will be discarded until existing events are processed.
(EE) 
(EE) Backtrace:
(EE) 0: /usr/bin/X (xorg_backtrace+0x56) [0x58bd66]
(EE) 1: /usr/bin/X (mieqEnqueue+0x24b) [0x56db3b]
(EE) 2: /usr/bin/X (QueuePointerEvents+0x52) [0x44e712]
(EE) 3: /usr/lib64/xorg/modules/input/evdev_drv.so (0x7f526fc4b000+0x625f) [0x7f526fc5125f]
(EE) 4: /usr/lib64/xorg/modules/input/evdev_drv.so (0x7f526fc4b000+0x6aed) [0x7f526fc51aed]
(EE) 5: /usr/bin/X (0x400000+0x75ab8) [0x475ab8]
(EE) 6: /usr/bin/X (0x400000+0x9b116) [0x49b116]
(EE) 7: /lib64/libc.so.6 (0x7f527aafa000+0x33290) [0x7f527ab2d290]
(EE) 8: /lib64/libc.so.6 (ioctl+0x5) [0x7f527abdba55]
(EE) 9: /usr/lib64/libdrm.so.2 (drmIoctl+0x28) [0x7f527bc7dc68]
(EE) 10: /usr/lib64/libdrm.so.2 (drmCommandWrite+0x1b) [0x7f527bc8098b]
(EE) 11: /usr/lib64/libdrm_nouveau.so.2 (nouveau_bo_wait+0xbc) [0x7f5276a6c44c]
(EE) 12: /usr/lib64/libdrm_nouveau.so.2 (nouveau_pushbuf_space+0xde) [0x7f5276a6d85e]
(EE) 13: /usr/lib64/xorg/modules/drivers/nouveau_drv.so (0x7f5276c71000+0x23b21) [0x7f5276c94b21]
(EE) 14: /usr/lib64/xorg/modules/drivers/nouveau_drv.so (0x7f5276c71000+0x7c91) [0x7f5276c78c91]
(EE) 15: /usr/lib64/xorg/modules/libexa.so (0x7f527642a000+0x9de4) [0x7f5276433de4]
(EE) 16: /usr/lib64/xorg/modules/libexa.so (0x7f527642a000+0x9f2c) [0x7f5276433f2c]
(EE) 17: /usr/bin/X (miCopyRegion+0x1b3) [0x56bf73]
(EE) 18: /usr/bin/X (miDoCopy+0x44e) [0x56c51e]
(EE) 19: /usr/lib64/xorg/modules/libexa.so (0x7f527642a000+0x8545) [0x7f5276432545]
(EE) 20: /usr/bin/X (0x400000+0x117d81) [0x517d81]
(EE) 21: /usr/bin/X (0x400000+0xd13aa) [0x4d13aa]
(EE) 22: /usr/bin/X (0x400000+0xd2ad5) [0x4d2ad5]
(EE) 23: /usr/bin/X (0x400000+0x35faf) [0x435faf]
(EE) 24: /usr/bin/X (0x400000+0x3a033) [0x43a033]
(EE) 25: /lib64/libc.so.6 (__libc_start_main+0xf0) [0x7f527ab1a630]
(EE) 26: /usr/bin/X (_start+0x29) [0x424329]
(EE) 
(EE) [mi] These backtraces from mieqEnqueue may point to a culprit higher up the stack.
(EE) [mi] mieq is *NOT* the cause.  It is a victim.


.xsession-error:

kontact: /var/tmp/portage/x11-libs/libdrm-2.4.70/work/libdrm-2.4.70/nouveau/pushbuf.c:727: nouveau_pushbuf_data: Assertion »kref« failed.
*** KMail got signal 6 (Exiting)
*** Dead letters dumped.
[1105/184917:ERROR:gles2_cmd_decoder.cc(2109)] [.CommandBufferContext.RenderWorker-0x1a44370]GL ERROR :GL_OUT_OF_MEMORY : ScopedTextureBinder::dtor: <- error from previous GL command
[1105/184917:ERROR:gles2_cmd_decoder.cc(4471)] Error: 5 for Command kCopySubTextureCHROMIUM
[1105/184917:ERROR:gles2_cmd_decoder.cc(3579)]   GLES2DecoderImpl: Trying to make lost context current.
KCrash: Application 'kontact' crashing...