Application: kwin (4.11.9)
KDE Platform Version: 4.13.0
Qt Version: 4.8.6
Operating System: Linux 3.13.0-22-generic x86_64
Distribution: Ubuntu 14.04 LTS

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

1. Right click on a window title bar.
2. Navigate to the Activities context menu

- Unusual behavior I noticed:

Right after displaying the menu content and without any other action, Kwin crashes.
As a result, all windows from all running activities are brought back to the current activity desktop.

- Custom settings of the application:

N/A

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 0x7f0950a8e800 (LWP 3902))]

Thread 3 (Thread 0x7f09297c2700 (LWP 3961)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00007f094f45fffb in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#2  0x00007f094f460039 in ?? () from /usr/lib/x86_64-linux-gnu/libQtScript.so.4
#3  0x00007f0948004182 in start_thread (arg=0x7f09297c2700) at pthread_create.c:312
#4  0x00007f095027130d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 2 (Thread 0x7f093111a700 (LWP 5401)):
#0  0x00007f0950268c33 in select () at ../sysdeps/unix/syscall-template.S:81
#1  0x00007f094a6592c7 in qt_safe_select (nfds=21, fdread=0x7f0924000ac8, fdwrite=0x7f0924000d60, fdexcept=0x7f0924000ff8, orig_timeout=0x0) at kernel/qcore_unix.cpp:79
#2  0x00007f094a65e824 in QEventDispatcherUNIXPrivate::doSelect (this=this@entry=0x7f0924000910, flags=..., timeout=0x0) at kernel/qeventdispatcher_unix.cpp:223
#3  0x00007f094a65ec92 in QEventDispatcherUNIX::processEvents (this=0x7f09240008f0, flags=...) at kernel/qeventdispatcher_unix.cpp:936
#4  0x00007f094a62d0af in QEventLoop::processEvents (this=this@entry=0x7f0931119da0, flags=...) at kernel/qeventloop.cpp:149
#5  0x00007f094a62d3a5 in QEventLoop::exec (this=this@entry=0x7f0931119da0, flags=...) at kernel/qeventloop.cpp:204
#6  0x00007f094a529c5f in QThread::exec (this=this@entry=0x1433d00) at thread/qthread.cpp:537
#7  0x00007f094a60e823 in QInotifyFileSystemWatcherEngine::run (this=0x1433d00) at io/qfilesystemwatcher_inotify.cpp:265
#8  0x00007f094a52c32f in QThreadPrivate::start (arg=0x1433d00) at thread/qthread_unix.cpp:349
#9  0x00007f0948004182 in start_thread (arg=0x7f093111a700) at pthread_create.c:312
#10 0x00007f095027130d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 1 (Thread 0x7f0950a8e800 (LWP 3902)):
[KCrash Handler]
#6  begin (this=0x88) at ../../include/QtCore/../../src/corelib/tools/qlist.h:101
#7  contains (t=@0x7fff4d3be9a8: 0x19661e0, this=0x88) at ../../include/QtCore/../../src/corelib/tools/qlist.h:882
#8  QActionGroup::addAction (this=0x12a1400, a=a@entry=0x19661e0) at kernel/qactiongroup.cpp:180
#9  0x00007f09505dde9c in KWin::UserActionsMenu::activityPopupAboutToShow (this=0x803a80) at ../../kwin/useractions.cpp:723
#10 0x00007f094a64287a in QMetaObject::activate (sender=sender@entry=0x1dc2f20, m=m@entry=0x7f094a481340 <QMenu::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3539
#11 0x00007f0949df11c0 in QMenu::aboutToShow (this=this@entry=0x1dc2f20) at .moc/release-shared/moc_qmenu.cpp:164
#12 0x00007f0949df40bd in QMenu::popup (this=0x1dc2f20, p=..., atAction=atAction@entry=0x0) at widgets/qmenu.cpp:1844
#13 0x00007f0949df56fb in QMenu::internalDelayedPopup (this=this@entry=0x19b5000) at widgets/qmenu.cpp:3057
#14 0x00007f0949df7174 in QMenu::timerEvent (this=0x19b5000, e=<optimized out>) at widgets/qmenu.cpp:2917
#15 0x00007f094a646a31 in QObject::event (this=this@entry=0x19b5000, e=e@entry=0x7fff4d3bf220) at kernel/qobject.cpp:1156
#16 0x00007f0949a1755b in QWidget::event (this=this@entry=0x19b5000, event=event@entry=0x7fff4d3bf220) at kernel/qwidget.cpp:8846
#17 0x00007f0949df97bb in QMenu::event (this=0x19b5000, e=0x7fff4d3bf220) at widgets/qmenu.cpp:2481
#18 0x00007f09499c7e2c in QApplicationPrivate::notify_helper (this=this@entry=0x6a7450, receiver=receiver@entry=0x19b5000, e=e@entry=0x7fff4d3bf220) at kernel/qapplication.cpp:4567
#19 0x00007f09499ce4a0 in QApplication::notify (this=this@entry=0x7fff4d3c0260, receiver=receiver@entry=0x19b5000, e=e@entry=0x7fff4d3bf220) at kernel/qapplication.cpp:4353
#20 0x00007f094eeb4baa in KApplication::notify (this=0x7fff4d3c0260, receiver=0x19b5000, event=0x7fff4d3bf220) at ../../kdeui/kernel/kapplication.cpp:311
#21 0x00007f094a62e4dd in QCoreApplication::notifyInternal (this=0x7fff4d3c0260, receiver=0x19b5000, event=0x7fff4d3bf220) at kernel/qcoreapplication.cpp:953
#22 0x00007f094a65e323 in sendEvent (event=<optimized out>, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#23 QTimerInfoList::activateTimers (this=0x6a8078) at kernel/qeventdispatcher_unix.cpp:621
#24 0x00007f094a65e3a0 in QEventDispatcherUNIX::activateTimers (this=this@entry=0x645af0) at kernel/qeventdispatcher_unix.cpp:878
#25 0x00007f094a65ed20 in QEventDispatcherUNIX::processEvents (this=this@entry=0x645af0, flags=...) at kernel/qeventdispatcher_unix.cpp:940
#26 0x00007f0949a6a4d6 in QEventDispatcherX11::processEvents (this=0x645af0, flags=...) at kernel/qeventdispatcher_x11.cpp:152
#27 0x00007f094a62d0af in QEventLoop::processEvents (this=this@entry=0x7fff4d3bf570, flags=...) at kernel/qeventloop.cpp:149
#28 0x00007f094a62d3a5 in QEventLoop::exec (this=this@entry=0x7fff4d3bf570, flags=...) at kernel/qeventloop.cpp:204
#29 0x00007f0949df8587 in QMenu::exec (this=0x19b5000, p=..., action=action@entry=0x0) at widgets/qmenu.cpp:2125
#30 0x00007f09505da78a in KWin::UserActionsMenu::show (this=0x803a80, pos=..., cl=...) at ../../kwin/useractions.cpp:167
#31 0x00007f09505da84b in KWin::Workspace::showWindowMenu (this=0x7fd140, pos=..., cl=0x1938300) at ../../kwin/useractions.cpp:1827
#32 0x00007f09505cefc2 in KWin::Bridge::showWindowMenu (this=0x1999e40, p=..., id=<optimized out>) at ../../kwin/bridge.cpp:110
#33 0x00007f093177f65e in Oxygen::Client::mousePressEvent (this=0x31721e0, event=0x7fff4d3bfae0) at ../../../../kwin/clients/oxygen/oxygenclient.cpp:1669
#34 0x00007f0931788bda in Oxygen::Client::eventFilter (this=0x31721e0, object=0x34de200, event=0x7fff4d3bfae0) at ../../../../kwin/clients/oxygen/oxygenclient.cpp:1358
#35 0x00007f094a62e646 in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=this@entry=0x6a7450, receiver=receiver@entry=0x34de200, event=event@entry=0x7fff4d3bfae0) at kernel/qcoreapplication.cpp:1063
#36 0x00007f09499c7e0c in QApplicationPrivate::notify_helper (this=this@entry=0x6a7450, receiver=receiver@entry=0x34de200, e=e@entry=0x7fff4d3bfae0) at kernel/qapplication.cpp:4563
#37 0x00007f09499ce5dd in QApplication::notify (this=this@entry=0x7fff4d3c0260, receiver=receiver@entry=0x34de200, e=e@entry=0x7fff4d3bfae0) at kernel/qapplication.cpp:4110
#38 0x00007f094eeb4baa in KApplication::notify (this=0x7fff4d3c0260, receiver=0x34de200, event=0x7fff4d3bfae0) at ../../kdeui/kernel/kapplication.cpp:311
#39 0x00007f094a62e4dd in QCoreApplication::notifyInternal (this=0x7fff4d3c0260, receiver=receiver@entry=0x34de200, event=event@entry=0x7fff4d3bfae0) at kernel/qcoreapplication.cpp:953
#40 0x00007f09499cdd93 in sendEvent (event=<optimized out>, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#41 QApplicationPrivate::sendMouseEvent (receiver=receiver@entry=0x34de200, event=event@entry=0x7fff4d3bfae0, alienWidget=alienWidget@entry=0x0, nativeWidget=nativeWidget@entry=0x34de200, buttonDown=buttonDown@entry=0x7f094a4ad318 <qt_button_down>, lastMouseReceiver=..., spontaneous=spontaneous@entry=true) at kernel/qapplication.cpp:3178
#42 0x00007f0949a429cb in QETWidget::translateMouseEvent (this=this@entry=0x34de200, event=event@entry=0x7fff4d3bfe70) at kernel/qapplication_x11.cpp:4634
#43 0x00007f0949a42269 in QApplication::x11ProcessEvent (this=0x7fff4d3c0260, event=event@entry=0x7fff4d3bfe70) at kernel/qapplication_x11.cpp:3627
#44 0x00007f0949a6a470 in QEventDispatcherX11::processEvents (this=0x645af0, flags=...) at kernel/qeventdispatcher_x11.cpp:132
#45 0x00007f094a62d0af in QEventLoop::processEvents (this=this@entry=0x7fff4d3c00d0, flags=...) at kernel/qeventloop.cpp:149
#46 0x00007f094a62d3a5 in QEventLoop::exec (this=this@entry=0x7fff4d3c00d0, flags=...) at kernel/qeventloop.cpp:204
#47 0x00007f094a632b79 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1225
#48 0x00007f09499c637c in QApplication::exec () at kernel/qapplication.cpp:3828
#49 0x00007f09505b7906 in kdemain (argc=1, argv=0x7fff4d3c03a8) at ../../kwin/main.cpp:597
#50 0x00007f0950197ec5 in __libc_start_main (main=0x4006d0 <main(int, char**)>, argc=1, argv=0x7fff4d3c03a8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff4d3c0398) at libc-start.c:287
#51 0x00000000004006fe in _start ()

Possible duplicates by query: bug 335955, bug 335459, bug 335244, bug 335215, bug 334539.

Reported using DrKonqi