Application: kwin (4.10.5)
KDE Platform Version: 4.10.5
Qt Version: 4.8.4
Operating System: Linux 3.8.0-27-generic i686
Distribution: Ubuntu 13.04

-- Information about the crash:
- What I was doing when the application crashed:
I have logged in as guest (this was my first time as guest). I open the file manager (Dolphin) and clicked on a hard drive icon (the other harddisk in my computer, not the one on which KUbuntu is installed) and it asked me for password to mount it. After a second, it crashed and there was no window to fill in the password.
- Unusual behavior I noticed:
After the crash, there is no desktop background and no task bar, only the crash report windows. Before the crash, nothing was unusual.

-- Backtrace:
Application: KWin (kwin), signal: Segmentation fault
Using host libthread_db library "/lib/i386-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0xb1103740 (LWP 1927))]

Thread 2 (Thread 0xa99cab40 (LWP 1936)):
#0  0xb76e3424 in __kernel_vsyscall ()
#1  0xb216d84b in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/i386-linux-gnu/libpthread.so.0
#2  0xb74b9d7c in pthread_cond_wait () from /lib/i386-linux-gnu/libc.so.6
#3  0xb65d50ad in ?? () from /usr/lib/i386-linux-gnu/libQtScript.so.4
#4  0xb65d50df in ?? () from /usr/lib/i386-linux-gnu/libQtScript.so.4
#5  0xb2169d78 in start_thread () from /lib/i386-linux-gnu/libpthread.so.0
#6  0xb74ac3de in clone () from /lib/i386-linux-gnu/libc.so.6

Thread 1 (Thread 0xb1103740 (LWP 1927)):
[KCrash Handler]
#6  0xb74350f6 in free () from /lib/i386-linux-gnu/libc.so.6
#7  0xaca151b7 in nouveau_buffer_destroy (pscreen=0x9359d68, presource=0x9591888) at nouveau_buffer.c:112
#8  0xac2081e8 in u_resource_destroy_vtbl (screen=0x9359d68, resource=0x9591888) at util/u_resource.c:24
#9  0xac2a6799 in pipe_resource_reference (ptr=0x92fa438, tex=<optimized out>) at ../../../../../src/gallium/auxiliary/util/u_inlines.h:140
#10 st_bufferobj_data (ctx=0x93892d8, target=34962, size=48, data=0x932fd38, usage=35040, obj=0x92fa3f8) at ../../../../../src/mesa/state_tracker/st_cb_bufferobjects.c:232
#11 0xac5b3543 in _mesa_BufferData (target=34962, size=48, data=0x932fd38, usage=35040) at ../../../../../src/mesa/main/bufferobj.c:1078
#12 0xb6401f26 in KWin::GLVertexBuffer::setData (this=this@entry=0x93c6160, vertexCount=vertexCount@entry=6, dim=dim@entry=2, vertices=0x932fd38, texcoords=0x932fd38) at ../../../kwin/libkwineffects/kwinglutils.cpp:1347
#13 0xacd93762 in KWin::BlurEffect::drawRegion (this=this@entry=0x9524d20, region=...) at ../../../kwin/effects/blur/blur.cpp:253
#14 0xacd94816 in KWin::BlurEffect::doCachedBlur (this=this@entry=0x9524d20, w=w@entry=0x9587278, region=..., opacity=0.600000024) at ../../../kwin/effects/blur/blur.cpp:669
#15 0xacd95c1e in KWin::BlurEffect::drawWindow (this=0x9524d20, w=0x9587278, mask=10, region=..., data=...) at ../../../kwin/effects/blur/blur.cpp:411
#16 0xb7661553 in KWin::EffectsHandlerImpl::drawWindow (this=0x94cb4f8, w=w@entry=0x9587278, mask=mask@entry=10, region=..., data=...) at ../../kwin/effects.cpp:315
#17 0xb68ba1f2 in KWin::Effect::drawWindow (this=0x91da548, w=0x9587278, mask=10, region=..., data=...) at ../../../kwin/libkwineffects/kwineffects.cpp:529
#18 0xb7661553 in KWin::EffectsHandlerImpl::drawWindow (this=0x94cb4f8, w=w@entry=0x9587278, mask=mask@entry=10, region=..., data=...) at ../../kwin/effects.cpp:315
#19 0xb763bfb2 in KWin::Scene::finalPaintWindow (this=0x93c7f18, w=w@entry=0x9587278, mask=mask@entry=10, region=..., data=...) at ../../kwin/scene.cpp:449
#20 0xb7661893 in KWin::EffectsHandlerImpl::paintWindow (this=0x94cb4f8, w=w@entry=0x9587278, mask=mask@entry=10, region=..., data=...) at ../../kwin/effects.cpp:281
#21 0xb68ba312 in KWin::Effect::paintWindow (this=0x9524d20, w=0x9587278, mask=10, region=..., data=...) at ../../../kwin/libkwineffects/kwineffects.cpp:504
#22 0xb7661833 in KWin::EffectsHandlerImpl::paintWindow (this=0x94cb4f8, w=w@entry=0x9587278, mask=mask@entry=10, region=..., data=...) at ../../kwin/effects.cpp:278
#23 0xb68c9324 in KWin::AnimationEffect::paintWindow (this=0x91da548, w=0x9587278, mask=10, region=..., data=...) at ../../../kwin/libkwineffects/kwinanimationeffect.cpp:529
#24 0xb7661833 in KWin::EffectsHandlerImpl::paintWindow (this=0x94cb4f8, w=0x9587278, mask=mask@entry=10, region=..., data=...) at ../../kwin/effects.cpp:278
#25 0xb763f0f0 in KWin::Scene::paintWindow (this=this@entry=0x93c7f18, w=0x95931b8, mask=10, region=..., quads=...) at ../../kwin/scene.cpp:356
#26 0xb763e256 in KWin::Scene::paintSimpleScreen (this=this@entry=0x93c7f18, orig_mask=orig_mask@entry=8, region=...) at ../../kwin/scene.cpp:342
#27 0xb763bef3 in KWin::Scene::finalPaintScreen (this=0x93c7f18, mask=mask@entry=8, region=..., data=...) at ../../kwin/scene.cpp:186
#28 0xb76614b3 in KWin::EffectsHandlerImpl::paintScreen (this=0x94cb4f8, mask=mask@entry=8, region=..., data=...) at ../../kwin/effects.cpp:254
#29 0xb68ba38a in KWin::Effect::paintScreen (this=0x9524d20, mask=8, region=..., data=...) at ../../../kwin/libkwineffects/kwineffects.cpp:489
#30 0xb766145b in KWin::EffectsHandlerImpl::paintScreen (this=0x94cb4f8, mask=mask@entry=8, region=..., data=...) at ../../kwin/effects.cpp:251
#31 0xb68ba38a in KWin::Effect::paintScreen (this=0x91da548, mask=8, region=..., data=...) at ../../../kwin/libkwineffects/kwineffects.cpp:489
#32 0xb766145b in KWin::EffectsHandlerImpl::paintScreen (this=0x94cb4f8, mask=8, region=..., data=...) at ../../kwin/effects.cpp:251
#33 0xb763d48e in KWin::Scene::paintScreen (this=this@entry=0x93c7f18, mask=mask@entry=0xbfc6dc8c, region=region@entry=0xbfc6dcfc) at ../../kwin/scene.cpp:140
#34 0xb764c18b in KWin::SceneOpenGL::paint (this=0x93c7f18, damage=..., toplevels=...) at ../../kwin/scene_opengl.cpp:308
#35 0xb7635c60 in KWin::Compositor::performCompositing (this=0x92fda78) at ../../kwin/composite.cpp:610
#36 0xb5f002d4 in QObject::event(QEvent*) () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#37 0xb53d3c7c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/i386-linux-gnu/libQtGui.so.4
#38 0xb53d6b94 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/i386-linux-gnu/libQtGui.so.4
#39 0xb716a491 in KApplication::notify(QObject*, QEvent*) () from /usr/lib/libkdeui.so.5
#40 0xb75e2d2f in notify (e=0xbfc6e220, o=0x92fda78, this=0xbfc6e5e8) at ../../kwin/main.cpp:371
#41 KWin::Application::notify (this=0xbfc6e5e8, o=0x92fda78, e=0xbfc6e220) at ../../kwin/main.cpp:367
#42 0xb5ee490e in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#43 0xb5f198c0 in ?? () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#44 0xb5f19ab8 in QEventDispatcherUNIX::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#45 0xb548b5f3 in ?? () from /usr/lib/i386-linux-gnu/libQtGui.so.4
#46 0xb5ee33ec in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#47 0xb5ee36e1 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#48 0xb5ee93fa in QCoreApplication::exec() () from /usr/lib/i386-linux-gnu/libQtCore.so.4
#49 0xb53d1fc4 in QApplication::exec() () from /usr/lib/i386-linux-gnu/libQtGui.so.4
#50 0xb75e27e1 in kdemain (argc=1, argv=0xbfc6e6d4) at ../../kwin/main.cpp:537
#51 0x0804855b in main (argc=1, argv=0xbfc6e6d4) at kwin_dummy.cpp:3

Reported using DrKonqi