Application: kwin (4.11.8)
KDE Platform Version: 4.13.0
Qt Version: 4.8.6
Operating System: Linux 3.13.0-24-generic x86_64
Distribution: Ubuntu 14.04 LTS

-- Information about the crash:
- What I was doing when the application crashed:

Switching windows with alt-tab: kwin dies and gets restarted soon afterwards.

The crash can be reproduced sometimes.

-- 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 0x7f2dea5d8800 (LWP 2381))]

Thread 3 (Thread 0x7f2dcc938700 (LWP 2978)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f2de90b1ffb in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#2  0x00007f2de90b2039 in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#3  0x00007f2de1cda182 in start_thread (arg=0x7f2dcc938700) at pthread_create.c:312
#4  0x00007f2de9ec330d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 2 (Thread 0x7f2d45a07700 (LWP 2979)):
#0  0x00007f2de9ebac33 in select () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f2de432f2c7 in qt_safe_select (nfds=13, fdread=0x7f2dc8000ac8, fdwrite=0x7f2dc8000d60, fdexcept=0x7f2dc8000ff8, orig_timeout=0x0) at kernel/qcore_unix.cpp:79
#2  0x00007f2de4334824 in QEventDispatcherUNIXPrivate::doSelect (this=this@entry=0x7f2dc8000910, flags=..., timeout=0x0) at kernel/qeventdispatcher_unix.cpp:223
#3  0x00007f2de4334c92 in QEventDispatcherUNIX::processEvents (this=0x7f2dc80008f0, flags=...) at kernel/qeventdispatcher_unix.cpp:936
#4  0x00007f2de43030af in QEventLoop::processEvents (this=this@entry=0x7f2d45a06da0, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007f2de43033a5 in QEventLoop::exec (this=this@entry=0x7f2d45a06da0, flags=...) at kernel/qeventloop.cpp:204
#6  0x00007f2de41ffc5f in QThread::exec (this=this@entry=0x24ecc90) at thread/qthread.cpp:537
#7  0x00007f2de42e4823 in QInotifyFileSystemWatcherEngine::run (this=0x24ecc90) at io/qfilesystemwatcher_inotify.cpp:265
#8  0x00007f2de420232f in QThreadPrivate::start (arg=0x24ecc90) at thread/qthread_unix.cpp:349
#9  0x00007f2de1cda182 in start_thread (arg=0x7f2d45a07700) at pthread_create.c:312
#10 0x00007f2de9ec330d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 1 (Thread 0x7f2dea5d8800 (LWP 2381)):
[KCrash Handler]
#6  0x0000000000000000 in ?? ()
#7  0x00007f2dea2051ad in KWin::Workspace::constrainedStackingOrder (this=this@entry=0x20f1df0) at ../../kwin/layers.cpp:509
#8  0x00007f2dea205780 in KWin::Workspace::updateStackingOrder (this=this@entry=0x20f1df0, propagate_new_clients=<optimized out>) at ../../kwin/layers.cpp:117
#9  0x00007f2dea205b1d in updateStackingOrder (propagate_new_clients=<optimized out>, this=0x20f1df0) at ../../kwin/layers.cpp:609
#10 KWin::Workspace::blockStackingUpdates (this=this@entry=0x20f1df0, block=block@entry=false) at ../../kwin/layers.cpp:616
#11 0x00007f2dea1f5424 in ~StackingUpdatesBlocker (this=<synthetic pointer>, __in_chrg=<optimized out>) at ../../kwin/workspace.h:565
#12 KWin::Client::releaseWindow (this=this@entry=0x245e990, on_shutdown=on_shutdown@entry=false) at ../../kwin/client.cpp:317
#13 0x00007f2dea210eaa in KWin::Client::unmapNotifyEvent (this=0x245e990, e=<optimized out>) at ../../kwin/events.cpp:595
#14 0x00007f2dea212feb in KWin::Client::windowEvent (this=0x245e990, e=e@entry=0x7fff5b029180) at ../../kwin/events.cpp:451
#15 0x00007f2dea21462f in KWin::Workspace::workspaceEvent (this=0x20f1df0, e=e@entry=0x7fff5b029180) at ../../kwin/events.cpp:164
#16 0x00007f2dea208970 in KWin::Application::x11EventFilter (this=0x7fff5b029570, e=0x7fff5b029180) at ../../kwin/main.cpp:422
#17 0x00007f2de37065dc in qt_x11EventFilter (ev=0x7fff5b029180) at kernel/qapplication_x11.cpp:442
#18 0x00007f2de3716e40 in QApplication::x11ProcessEvent (this=0x7fff5b029570, event=event@entry=0x7fff5b029180) at kernel/qapplication_x11.cpp:3461
#19 0x00007f2de3740470 in QEventDispatcherX11::processEvents (this=0x1f25af0, flags=...) at kernel/qeventdispatcher_x11.cpp:132
#20 0x00007f2de43030af in QEventLoop::processEvents (this=this@entry=0x7fff5b0293e0, flags=...) at kernel/qeventloop.cpp:149
#21 0x00007f2de43033a5 in QEventLoop::exec (this=this@entry=0x7fff5b0293e0, flags=...) at kernel/qeventloop.cpp:204
#22 0x00007f2de4308b79 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1225
#23 0x00007f2de369c37c in QApplication::exec () at kernel/qapplication.cpp:3828
#24 0x00007f2dea209856 in kdemain (argc=3, argv=0x7fff5b0296b8) at ../../kwin/main.cpp:597
#25 0x00007f2de9de9ec5 in __libc_start_main (main=0x4006d0 <main(int, char**)>, argc=3, argv=0x7fff5b0296b8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff5b0296a8) at libc-start.c:287
#26 0x00000000004006fe in _start ()

Possible duplicates by query: bug 333471, bug 333384, bug 333381, bug 333313, bug 330965.

Reported using DrKonqi