Application: kwin (4.9.3)
KDE Platform Version: 4.9.3
Qt Version: 4.8.2
Operating System: Linux 3.2.0-34-generic-pae i686
Distribution: Ubuntu 12.04.1 LTS

-- Information about the crash:
I've been giving Kwin tiling a test drive for a couple of days now. It worked quite fine until the momen I run xsane. While starting there should have been (and were) two usual and two free windows opened. But after the start-up was done Kwin crashed and restarted itself.

-- 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 0xafe53740 (LWP 2245))]

Thread 2 (Thread 0xaa916b40 (LWP 2251)):
#0  0xb7773424 in __kernel_vsyscall ()
#1  0xb29f196b in pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/i386/i686/../i486/pthread_cond_wait.S:169
#2  0xb754b64c in __pthread_cond_wait (cond=0xb6799890, mutex=0xb6799878) at forward.c:139
#3  0xb6695029 in QTWTF::TCMalloc_PageHeap::scavengerThread (this=0xb67947a0) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:2359
#4  0xb669506f in QTWTF::TCMalloc_PageHeap::runScavengerThread (context=0xb67947a0) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:1464
#5  0xb649da11 in ?? () from /usr/lib/nvidia-current/libGL.so.1
#6  0x5c8b0824 in ?? ()
#7  0xbab80424 in ?? ()
#8  0x65000000 in ?? ()
#9  0x001015ff in ?? ()
#10 0xd3890000 in ?? ()
#11 0xfff0013d in ?? ()
#12 0xc30173ff in ?? ()
#13 0x0fc3a2e8 in ?? ()
#14 0xafc18100 in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)

Thread 1 (Thread 0xafe53740 (LWP 2245)):
[KCrash Handler]
#7  0xb76c2ba9 in count (this=0x8e2aab8) at /usr/include/qt4/QtCore/qvector.h:259
#8  KWin::WindowRules::checkSize (this=0x8e2aab8, arg=..., init=false) at ../../kwin/rules.cpp:782
#9  0xb76c2c96 in KWin::WindowRules::checkGeometry (this=0x8e2aab8, rect=..., init=false) at ../../kwin/rules.cpp:778
#10 0xb76adee7 in KWin::Client::setGeometry (this=0x8e2a978, x=960, y=556, w=960, h=524, force=KWin::ForceGeometrySet) at ../../kwin/geometry.cpp:1870
#11 0xb77241d3 in setGeometry (force=KWin::ForceGeometrySet, r=..., this=<optimized out>) at ../../kwin/client.h:1202
#12 KWin::Tile::commit (this=0x89611d0) at ../../kwin/tiling/tile.cpp:66
#13 0xb7728cc0 in KWin::TilingLayout::commit (this=0x856ed70) at ../../kwin/tiling/tilinglayout.cpp:222
#14 0xb77260c4 in KWin::Tiling::updateAllTiles (this=0x834a768) at ../../kwin/tiling/tiling.cpp:207
#15 0xb76b5b36 in KWin::Client::handleMoveResize (this=0x8c7d658, x=214, y=72, x_root=454, y_root=82) at ../../kwin/geometry.cpp:3074
#16 0xb767ea53 in motionNotifyEvent (y_root=82, x_root=454, y=72, x=214, state=256, w=29375978, this=0x8c7d658) at ../../kwin/events.cpp:1385
#17 KWin::Client::motionNotifyEvent (this=0x8c7d658, w=29375978, state=256, x=214, y=72, x_root=454, y_root=82) at ../../kwin/events.cpp:1357
#18 0xb767ef7c in KWin::Client::eventFilter (this=0x8c7d658, o=0x8c23ed0, e=0xbfaa2e74) at ../../kwin/events.cpp:1053
#19 0xb5f5ff76 in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=0x8214fa0, receiver=0x8c23ed0, event=0xbfaa2e74) at kernel/qcoreapplication.cpp:1025
#20 0xb544adc2 in notify_helper (e=0xbfaa2e74, receiver=0x8c23ed0, this=0x8214fa0) at kernel/qapplication.cpp:4552
#21 QApplicationPrivate::notify_helper (this=0x8214fa0, receiver=0x8c23ed0, e=0xbfaa2e74) at kernel/qapplication.cpp:4528
#22 0xb5450e74 in QApplication::notify (this=0x8214fa0, receiver=0x8c23ed0, e=0xbfaa2e74) at kernel/qapplication.cpp:4099
#23 0xb71f7571 in KApplication::notify (this=0xbfaa3554, receiver=0x8c23ed0, event=0xbfaa2e74) at ../../kdeui/kernel/kapplication.cpp:311
#24 0xb767067f in notify (e=0xbfaa2e74, o=0x8c23ed0, this=0xbfaa3554) at ../../kwin/main.cpp:371
#25 KWin::Application::notify (this=0xbfaa3554, o=0x8c23ed0, e=0xbfaa2e74) at ../../kwin/main.cpp:367
#26 0xb5f5fdde in QCoreApplication::notifyInternal (this=0xbfaa3554, receiver=0x8c23ed0, event=0xbfaa2e74) at kernel/qcoreapplication.cpp:915
#27 0xb544bdb5 in sendEvent (event=<optimized out>, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#28 QApplicationPrivate::sendMouseEvent (receiver=0x8c23ed0, event=0xbfaa2e74, alienWidget=0x0, nativeWidget=0x8c23ed0, buttonDown=0xb5ddfcf4, lastMouseReceiver=..., spontaneous=true) at kernel/qapplication.cpp:3167
#29 0xb54d7f94 in QETWidget::translateMouseEvent (this=0x8c23ed0, event=0xbfaa332c) at kernel/qapplication_x11.cpp:4617
#30 0xb54d6b2d in QApplication::x11ProcessEvent (this=0xbfaa3554, event=0xbfaa332c) at kernel/qapplication_x11.cpp:3732
#31 0xb55049f8 in QEventDispatcherX11::processEvents (this=0x8181ea0, flags=...) at kernel/qeventdispatcher_x11.cpp:132
#32 0xb5f5e67d in QEventLoop::processEvents (this=0xbfaa34b4, flags=...) at kernel/qeventloop.cpp:149
#33 0xb5f5e919 in QEventLoop::exec (this=0xbfaa34b4, flags=...) at kernel/qeventloop.cpp:204
#34 0xb5f6431a in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1187
#35 0xb54489c4 in QApplication::exec () at kernel/qapplication.cpp:3817
#36 0xb7673536 in kdemain (argc=1, argv=0xbfaa37f4) at ../../kwin/main.cpp:545
#37 0x0804850b in main (argc=1, argv=0xbfaa37f4) at kwin_dummy.cpp:3

Reported using DrKonqi