Application: kwin (4.11.9)
KDE Platform Version: 4.13.1
Qt Version: 4.8.6
Operating System: Linux 3.13.0-30-generic x86_64
Distribution: Ubuntu 14.04 LTS

-- Information about the crash:
- What I was doing when the application crashed:
I had just done an update, which indicated that a restart was needed.  I restarted.  I started thunderbird and firefox, an noticed I didn't like their placement on the screen.  So I wanted to do Special Application Settings to "remember" the previous placement and screen size.  I left-clicked on the top bar in thunderbird, selected More Actions -> Special Application Settings -> Size & Position tab, and set Position, Size, & Fullscreen to "Remember".  So far so good.  Then left-clicked on the top bar for Firefox, I think but am not sure I clicked on More Actions and Special Application Settings.  I got the Kwin crash notice before I even saw the Size & Position tab.

- Custom settings of the application:
I don't recall any custom setting I may have made long ago to Firefox.  I probably did set font to a non-serif font.

-- Backtrace:
Application: KWin (kwin), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[KCrash Handler]
#6  begin (this=0x100000087) at ../../include/QtCore/../../src/corelib/tools/qlist.h:101
#7  contains (t=@0x7fff2d59e308: 0x1bfcda0, this=0x100000087) at ../../include/QtCore/../../src/corelib/tools/qlist.h:882
#8  QActionGroup::addAction (this=0x1ec4cd0, a=a@entry=0x1bfcda0) at kernel/qactiongroup.cpp:180
#9  0x00007f4a2d850e9c in KWin::UserActionsMenu::activityPopupAboutToShow (this=0x1a0ea00) at ../../kwin/useractions.cpp:723
#10 0x00007f4a277e887a in QMetaObject::activate (sender=sender@entry=0x1e65b70, m=m@entry=0x7f4a27627340 <QMenu::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3539
#11 0x00007f4a26f971c0 in QMenu::aboutToShow (this=this@entry=0x1e65b70) at .moc/release-shared/moc_qmenu.cpp:164
#12 0x00007f4a26f9a0bd in QMenu::popup (this=0x1e65b70, p=..., atAction=atAction@entry=0x0) at widgets/qmenu.cpp:1844
#13 0x00007f4a26f9b6fb in QMenu::internalDelayedPopup (this=this@entry=0x1da76c0) at widgets/qmenu.cpp:3057
#14 0x00007f4a26f9d174 in QMenu::timerEvent (this=0x1da76c0, e=<optimized out>) at widgets/qmenu.cpp:2917
#15 0x00007f4a277eca31 in QObject::event (this=this@entry=0x1da76c0, e=e@entry=0x7fff2d59eb80) at kernel/qobject.cpp:1156
#16 0x00007f4a26bbd55b in QWidget::event (this=this@entry=0x1da76c0, event=event@entry=0x7fff2d59eb80) at kernel/qwidget.cpp:8846
#17 0x00007f4a26f9f7bb in QMenu::event (this=0x1da76c0, e=0x7fff2d59eb80) at widgets/qmenu.cpp:2481
#18 0x00007f4a26b6de2c in QApplicationPrivate::notify_helper (this=this@entry=0x1866d20, receiver=receiver@entry=0x1da76c0, e=e@entry=0x7fff2d59eb80) at kernel/qapplication.cpp:4567
#19 0x00007f4a26b744a0 in QApplication::notify (this=this@entry=0x7fff2d59fbc0, receiver=receiver@entry=0x1da76c0, e=e@entry=0x7fff2d59eb80) at kernel/qapplication.cpp:4353
#20 0x00007f4a2c127d1a in KApplication::notify (this=0x7fff2d59fbc0, receiver=0x1da76c0, event=0x7fff2d59eb80) at ../../kdeui/kernel/kapplication.cpp:311
#21 0x00007f4a277d44dd in QCoreApplication::notifyInternal (this=0x7fff2d59fbc0, receiver=0x1da76c0, event=0x7fff2d59eb80) at kernel/qcoreapplication.cpp:953
#22 0x00007f4a27804323 in sendEvent (event=<optimized out>, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#23 QTimerInfoList::activateTimers (this=0x1867948) at kernel/qeventdispatcher_unix.cpp:621
#24 0x00007f4a278043a0 in QEventDispatcherUNIX::activateTimers (this=this@entry=0x17b2af0) at kernel/qeventdispatcher_unix.cpp:878
#25 0x00007f4a27804d20 in QEventDispatcherUNIX::processEvents (this=this@entry=0x17b2af0, flags=...) at kernel/qeventdispatcher_unix.cpp:940
#26 0x00007f4a26c104d6 in QEventDispatcherX11::processEvents (this=0x17b2af0, flags=...) at kernel/qeventdispatcher_x11.cpp:152
#27 0x00007f4a277d30af in QEventLoop::processEvents (this=this@entry=0x7fff2d59eed0, flags=...) at kernel/qeventloop.cpp:149
#28 0x00007f4a277d33a5 in QEventLoop::exec (this=this@entry=0x7fff2d59eed0, flags=...) at kernel/qeventloop.cpp:204
#29 0x00007f4a26f9e587 in QMenu::exec (this=0x1da76c0, p=..., action=action@entry=0x0) at widgets/qmenu.cpp:2125
#30 0x00007f4a2d84d78a in KWin::UserActionsMenu::show (this=0x1a0ea00, pos=..., cl=...) at ../../kwin/useractions.cpp:167
#31 0x00007f4a2d84d84b in KWin::Workspace::showWindowMenu (this=0x1a02580, pos=..., cl=0x1b00560) at ../../kwin/useractions.cpp:1827
#32 0x00007f4a2d841fc2 in KWin::Bridge::showWindowMenu (this=0x1af8130, p=..., id=<optimized out>) at ../../kwin/bridge.cpp:110
#33 0x00007f4a0cc1565e in Oxygen::Client::mousePressEvent (this=0x1b2dd20, event=0x7fff2d59f440) at ../../../../kwin/clients/oxygen/oxygenclient.cpp:1669
#34 0x00007f4a0cc1ebda in Oxygen::Client::eventFilter (this=0x1b2dd20, object=0x1b2dcd0, event=0x7fff2d59f440) at ../../../../kwin/clients/oxygen/oxygenclient.cpp:1358
#35 0x00007f4a277d4646 in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=this@entry=0x1866d20, receiver=receiver@entry=0x1b2dcd0, event=event@entry=0x7fff2d59f440) at kernel/qcoreapplication.cpp:1063
#36 0x00007f4a26b6de0c in QApplicationPrivate::notify_helper (this=this@entry=0x1866d20, receiver=receiver@entry=0x1b2dcd0, e=e@entry=0x7fff2d59f440) at kernel/qapplication.cpp:4563
#37 0x00007f4a26b745dd in QApplication::notify (this=this@entry=0x7fff2d59fbc0, receiver=receiver@entry=0x1b2dcd0, e=e@entry=0x7fff2d59f440) at kernel/qapplication.cpp:4110
#38 0x00007f4a2c127d1a in KApplication::notify (this=0x7fff2d59fbc0, receiver=0x1b2dcd0, event=0x7fff2d59f440) at ../../kdeui/kernel/kapplication.cpp:311
#39 0x00007f4a277d44dd in QCoreApplication::notifyInternal (this=0x7fff2d59fbc0, receiver=receiver@entry=0x1b2dcd0, event=event@entry=0x7fff2d59f440) at kernel/qcoreapplication.cpp:953
#40 0x00007f4a26b73d93 in sendEvent (event=<optimized out>, receiver=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#41 QApplicationPrivate::sendMouseEvent (receiver=receiver@entry=0x1b2dcd0, event=event@entry=0x7fff2d59f440, alienWidget=alienWidget@entry=0x0, nativeWidget=nativeWidget@entry=0x1b2dcd0, buttonDown=buttonDown@entry=0x7f4a27653318 <qt_button_down>, lastMouseReceiver=..., spontaneous=spontaneous@entry=true) at kernel/qapplication.cpp:3178
#42 0x00007f4a26be89cb in QETWidget::translateMouseEvent (this=this@entry=0x1b2dcd0, event=event@entry=0x7fff2d59f7d0) at kernel/qapplication_x11.cpp:4634
#43 0x00007f4a26be8269 in QApplication::x11ProcessEvent (this=0x7fff2d59fbc0, event=event@entry=0x7fff2d59f7d0) at kernel/qapplication_x11.cpp:3627
#44 0x00007f4a26c10470 in QEventDispatcherX11::processEvents (this=0x17b2af0, flags=...) at kernel/qeventdispatcher_x11.cpp:132
#45 0x00007f4a277d30af in QEventLoop::processEvents (this=this@entry=0x7fff2d59fa30, flags=...) at kernel/qeventloop.cpp:149
#46 0x00007f4a277d33a5 in QEventLoop::exec (this=this@entry=0x7fff2d59fa30, flags=...) at kernel/qeventloop.cpp:204
#47 0x00007f4a277d8b79 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1225
#48 0x00007f4a26b6c37c in QApplication::exec () at kernel/qapplication.cpp:3828
#49 0x00007f4a2d82a906 in kdemain (argc=3, argv=0x7fff2d59fd08) at ../../kwin/main.cpp:597
#50 0x00007f4a2d40aec5 in __libc_start_main (main=0x4006d0 <main(int, char**)>, argc=3, argv=0x7fff2d59fd08, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fff2d59fcf8) at libc-start.c:287
#51 0x00000000004006fe in _start ()

Possible duplicates by query: bug 336006, bug 335955, bug 335459, bug 335244, bug 335215.

Reported using DrKonqi