Application: kwin (4.11.8)
KDE Platform Version: 4.11.5
Qt Version: 4.8.6
Operating System: Linux 3.13-1-amd64 x86_64
Distribution: Debian GNU/Linux testing (jessie)

-- Information about the crash:
This problem occurs every time I try to enable desktop effects (Shift-Alt-F12).

The crash can be reproduced every time.

-- Backtrace:
Application: KWin (kwin), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f6ffadcd900 (LWP 5470))]

Thread 2 (Thread 0x7f6fd7de9700 (LWP 5476)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f6ff97b7b4b in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#2  0x00007f6ff97b7b89 in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#3  0x00007f6ff231b062 in start_thread (arg=0x7f6fd7de9700) at pthread_create.c:312
#4  0x00007f6ffa5b3a3d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 1 (Thread 0x7f6ffadcd900 (LWP 5470)):
[KCrash Handler]
#6  pushbuf_dump (krec=krec@entry=0x18a0680, krec_id=krec_id@entry=0, chid=0) at ../../nouveau/pushbuf.c:296
#7  0x00007f6f4b9b912c in pushbuf_submit (push=push@entry=0x15ad380, chan=<optimized out>, chan=<optimized out>) at ../../nouveau/pushbuf.c:361
#8  0x00007f6f4b9b916e in pushbuf_flush (push=push@entry=0x15ad380) at ../../nouveau/pushbuf.c:402
#9  0x00007f6f4b9b9a60 in pushbuf_validate (push=0x15ad380, retry=<optimized out>) at ../../nouveau/pushbuf.c:524
#10 0x00007f6f4b9b9bba in nouveau_pushbuf_validate (push=<optimized out>) at ../../nouveau/pushbuf.c:749
#11 0x00007f6f43a1ec1d in nv50_state_validate (nv50=nv50@entry=0x1298750, mask=mask@entry=4294967295, words=words@entry=8) at ../../../../../../src/gallium/drivers/nouveau/nv50/nv50_state_validate.c:430
#12 0x00007f6f43a29324 in nv50_draw_vbo (pipe=0x1298750, info=0x7fff1b02e470) at ../../../../../../src/gallium/drivers/nouveau/nv50/nv50_vbo.c:774
#13 0x00007f6f4379e75c in st_draw_vbo (ctx=0x7f6f4ab06010, prims=<optimized out>, nr_prims=<optimized out>, ib=0x7fff1b02e530, index_bounds_valid=<optimized out>, min_index=4294967295, max_index=4294967295, tfb_vertcount=0x0, indirect=0x0) at ../../../../src/mesa/state_tracker/st_draw.c:286
#14 0x00007f6f43770b73 in vbo_handle_primitive_restart (ctx=ctx@entry=0x7f6f4ab06010, prim=prim@entry=0x7fff1b02e550, nr_prims=nr_prims@entry=1, ib=ib@entry=0x7fff1b02e530, index_bounds_valid=index_bounds_valid@entry=0 '\000', min_index=min_index@entry=4294967295, max_index=max_index@entry=4294967295) at ../../../../src/mesa/vbo/vbo_exec_array.c:585
#15 0x00007f6f43771e90 in vbo_validated_drawrangeelements (ctx=ctx@entry=0x7f6f4ab06010, mode=mode@entry=4, index_bounds_valid=index_bounds_valid@entry=0 '\000', start=start@entry=4294967295, end=end@entry=4294967295, count=count@entry=96, type=type@entry=5123, indices=indices@entry=0x0, basevertex=basevertex@entry=0, numInstances=numInstances@entry=1, baseInstance=baseInstance@entry=0) at ../../../../src/mesa/vbo/vbo_exec_array.c:1006
#16 0x00007f6f43772325 in vbo_exec_DrawElementsBaseVertex (mode=4, count=96, type=5123, indices=0x0, basevertex=0) at ../../../../src/mesa/vbo/vbo_exec_array.c:1179
#17 0x00007f6ff56692db in KWin::GLVertexBuffer::draw (this=this@entry=0x17d0340, region=..., primitiveMode=primitiveMode@entry=7, first=0, count=96, hardwareClipping=<optimized out>) at ../../../kwin/libkwineffects/kwinglutils.cpp:1936
#18 0x00007f6ffa952958 in KWin::SceneOpenGL2Window::performPaint (this=this@entry=0x1e3ea30, mask=mask@entry=1, region=..., data=...) at ../../kwin/scene_opengl.cpp:1574
#19 0x00007f6ffa9563c2 in KWin::SceneOpenGL2::performPaintWindow (this=<optimized out>, w=<optimized out>, mask=1, region=..., data=...) at ../../kwin/scene_opengl.cpp:784
#20 0x00007f6ffa956579 in KWin::SceneOpenGL2::finalDrawWindow (this=0x124a810, w=w@entry=0x1e3e960, mask=mask@entry=1, region=..., data=...) at ../../kwin/scene_opengl.cpp:770
#21 0x00007f6ffa960d89 in KWin::EffectsHandlerImpl::drawWindow (this=0x1a78480, w=w@entry=0x1e3e960, mask=mask@entry=1, region=..., data=...) at ../../kwin/effects.cpp:455
#22 0x00007f6ffa93e871 in KWin::Scene::finalPaintWindow (this=<optimized out>, w=w@entry=0x1e3e960, mask=mask@entry=1, region=..., data=...) at ../../kwin/scene.cpp:584
#23 0x00007f6ffa960c9a in KWin::EffectsHandlerImpl::paintWindow (this=0x1a78480, w=0x1e3e960, mask=mask@entry=1, region=..., data=...) at ../../kwin/effects.cpp:418
#24 0x00007f6ffa9423da in KWin::Scene::paintWindow (this=0x124a810, w=0x1e3ea30, mask=1, region=..., quads=...) at ../../kwin/scene.cpp:416
#25 0x00007f6ffa9407cb in KWin::Scene::paintSimpleScreen (this=this@entry=0x124a810, orig_mask=orig_mask@entry=0, region=...) at ../../kwin/scene.cpp:378
#26 0x00007f6ffa93e755 in KWin::Scene::finalPaintScreen (this=0x124a810, mask=mask@entry=0, region=..., data=...) at ../../kwin/scene.cpp:198
#27 0x00007f6ffa960bbd in KWin::EffectsHandlerImpl::paintScreen (this=0x1a78480, mask=0, region=..., data=...) at ../../kwin/effects.cpp:375
#28 0x00007f6ffa940c23 in KWin::Scene::paintScreen (this=this@entry=0x124a810, mask=mask@entry=0x7fff1b02eecc, damage=..., repaint=..., updateRegion=updateRegion@entry=0x7fff1b02eee0, validRegion=validRegion@entry=0x7fff1b02eef0) at ../../kwin/scene.cpp:148
#29 0x00007f6ffa953a1e in KWin::SceneOpenGL::paint (this=0x124a810, damage=..., toplevels=...) at ../../kwin/scene_opengl.cpp:389
#30 0x00007f6ffa938873 in KWin::Compositor::performCompositing (this=this@entry=0xc24130) at ../../kwin/composite.cpp:618
#31 0x00007f6ffa939b6f in KWin::Compositor::slotCompositingOptionsInitialized (this=0xc24130) at ../../kwin/composite.cpp:273
#32 0x00007f6ffa8c27d5 in KWin::Compositor::qt_static_metacall (_o=<optimized out>, _id=<optimized out>, _a=<optimized out>, _c=<optimized out>) at moc_composite.cpp:193
#33 0x00007f6ff494d77a in QMetaObject::activate (sender=0x16718b0, m=<optimized out>, local_signal_index=<optimized out>, argv=0x0) at kernel/qobject.cpp:3539
#34 0x00007f6ff4827b18 in QFutureWatcherBase::event (this=<optimized out>, event=0x7f6fd8001d60) at concurrent/qfuturewatcher.cpp:344
#35 0x00007f6ff3cda6cc in QApplicationPrivate::notify_helper (this=this@entry=0xa214d0, receiver=receiver@entry=0x16718b0, e=e@entry=0x7f6fd8001d60) at kernel/qapplication.cpp:4567
#36 0x00007f6ff3ce0d40 in QApplication::notify (this=this@entry=0x7fff1b02fa20, receiver=receiver@entry=0x16718b0, e=e@entry=0x7f6fd8001d60) at kernel/qapplication.cpp:4353
#37 0x00007f6ff920748a in KApplication::notify (this=0x7fff1b02fa20, receiver=0x16718b0, event=0x7f6fd8001d60) at ../../kdeui/kernel/kapplication.cpp:311
#38 0x00007f6ff49394ed in QCoreApplication::notifyInternal (this=0x7fff1b02fa20, receiver=receiver@entry=0x16718b0, event=event@entry=0x7f6fd8001d60) at kernel/qcoreapplication.cpp:953
#39 0x00007f6ff493cb4d in sendEvent (event=0x7f6fd8001d60, receiver=0x16718b0) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#40 QCoreApplicationPrivate::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0, data=0x9b4300) at kernel/qcoreapplication.cpp:1577
#41 0x00007f6ff493cff3 in QCoreApplication::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0) at kernel/qcoreapplication.cpp:1470
#42 0x00007f6ff3d78eec in sendPostedEvents () at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:236
#43 QEventDispatcherX11::processEvents (this=0x9b5b30, flags=...) at kernel/qeventdispatcher_x11.cpp:75
#44 0x00007f6ff49380bf in QEventLoop::processEvents (this=this@entry=0x7fff1b02f890, flags=...) at kernel/qeventloop.cpp:149
#45 0x00007f6ff49383b5 in QEventLoop::exec (this=this@entry=0x7fff1b02f890, flags=...) at kernel/qeventloop.cpp:204
#46 0x00007f6ff493db89 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1225
#47 0x00007f6ff3cd8e8c in QApplication::exec () at kernel/qapplication.cpp:3828
#48 0x00007f6ffa8f28d6 in kdemain (argc=3, argv=0x7fff1b02fb68) at ../../kwin/main.cpp:597
#49 0x00007f6ffa4efb45 in __libc_start_main (main=0x4006d0 <main(int, char**)>, argc=3, argv=0x7fff1b02fb68, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff1b02fb58) at libc-start.c:287
#50 0x00000000004006fe in _start ()

Reported using DrKonqi