Application: kwin (4.11.8)
KDE Platform Version: 4.12.3
Qt Version: 4.8.5
Operating System: Linux 3.13.9-200.fc20.x86_64 x86_64
Distribution: "Fedora release 20 (Heisenbug)"

-- Information about the crash:
1. Have Wacom tablet plugged in.
2. Had pressed ctrl and the left mouse button on the wacom pen and was trying to move the pen over the tablet.

The crash can be reproduced every time.

-- Backtrace:
Application: KWin (kwin), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
81	T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
[Current thread is 1 (Thread 0x7f2d752db900 (LWP 2047))]

Thread 2 (Thread 0x7f2d4d9ec700 (LWP 2505)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f2d743a509b in QTWTF::TCMalloc_PageHeap::scavengerThread (this=0x7f2d746a3f00 <QTWTF::pageheap_memory>) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:2359
#2  0x00007f2d743a50d9 in QTWTF::TCMalloc_PageHeap::runScavengerThread (context=<optimized out>) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:1464
#3  0x00007f2d6eb33f33 in start_thread (arg=0x7f2d4d9ec700) at pthread_create.c:309
#4  0x00007f2d6cd21ded in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 1 (Thread 0x7f2d752db900 (LWP 2047)):
[KCrash Handler]
#6  0x00000000022ae760 in ?? ()
#7  0x00007f2d74f16b1d in KWin::Workspace::constrainedStackingOrder (this=this@entry=0x1e4afe0) at /usr/src/debug/kde-workspace-4.11.8/kwin/layers.cpp:509
#8  0x00007f2d74f17110 in KWin::Workspace::updateStackingOrder (this=this@entry=0x1e4afe0, propagate_new_clients=<optimized out>) at /usr/src/debug/kde-workspace-4.11.8/kwin/layers.cpp:117
#9  0x00007f2d74f174fd in updateStackingOrder (propagate_new_clients=<optimized out>, this=0x1e4afe0) at /usr/src/debug/kde-workspace-4.11.8/kwin/layers.cpp:609
#10 KWin::Workspace::blockStackingUpdates (this=this@entry=0x1e4afe0, block=block@entry=false) at /usr/src/debug/kde-workspace-4.11.8/kwin/layers.cpp:616
#11 0x00007f2d74f0672b in ~StackingUpdatesBlocker (this=<synthetic pointer>, __in_chrg=<optimized out>) at /usr/src/debug/kde-workspace-4.11.8/kwin/workspace.h:565
#12 KWin::Client::destroyClient (this=this@entry=0x21af7c0) at /usr/src/debug/kde-workspace-4.11.8/kwin/client.cpp:355
#13 0x00007f2d74f22df1 in KWin::Client::unmapNotifyEvent (this=0x21af7c0, e=<optimized out>) at /usr/src/debug/kde-workspace-4.11.8/kwin/events.cpp:597
#14 0x00007f2d74f2510b in KWin::Client::windowEvent (this=0x21af7c0, e=e@entry=0x7fff499bd790) at /usr/src/debug/kde-workspace-4.11.8/kwin/events.cpp:451
#15 0x00007f2d74f2682f in KWin::Workspace::workspaceEvent (this=0x1e4afe0, e=e@entry=0x7fff499bd790) at /usr/src/debug/kde-workspace-4.11.8/kwin/events.cpp:164
#16 0x00007f2d74f1a510 in KWin::Application::x11EventFilter (this=0x7fff499bdba0, e=0x7fff499bd790) at /usr/src/debug/kde-workspace-4.11.8/kwin/main.cpp:422
#17 0x00007f2d6e084dec in qt_x11EventFilter (ev=0x7fff499bd790) at kernel/qapplication_x11.cpp:435
#18 0x00007f2d6e092c09 in QApplication::x11ProcessEvent (this=0x7fff499bdba0, event=event@entry=0x7fff499bd790) at kernel/qapplication_x11.cpp:3373
#19 0x00007f2d6e0bb570 in QEventDispatcherX11::processEvents (this=0x1c93c80, flags=...) at kernel/qeventdispatcher_x11.cpp:132
#20 0x00007f2d6eecbedf in QEventLoop::processEvents (this=this@entry=0x7fff499bd9f0, flags=...) at kernel/qeventloop.cpp:149
#21 0x00007f2d6eecc22d in QEventLoop::exec (this=this@entry=0x7fff499bd9f0, flags=...) at kernel/qeventloop.cpp:204
#22 0x00007f2d6eed1749 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1221
#23 0x00007f2d6e0173fc in QApplication::exec () at kernel/qapplication.cpp:3823
#24 0x00007f2d74f1b411 in kdemain (argc=3, argv=0x7fff499bdcf8) at /usr/src/debug/kde-workspace-4.11.8/kwin/main.cpp:597
#25 0x00007f2d6cc4ed65 in __libc_start_main (main=0x4009d0 <main(int, char**)>, argc=3, argv=0x7fff499bdcf8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff499bdce8) at libc-start.c:285
#26 0x0000000000400a01 in _start ()

Possible duplicates by query: bug 333381, bug 333313, bug 330965, bug 326416, bug 326376.

Reported using DrKonqi