Application: kwin (4.11.9)
KDE Platform Version: 4.12.4
Qt Version: 4.8.6
Operating System: Linux 3.14.2-200.fc20.x86_64 x86_64
Distribution: "Fedora release 20 (Heisenbug)"

-- Information about the crash:
- What I was doing when the application crashed:
hovering the mouse on and off the window bar of the kmail application (later the same crash happened with another application)

- Unusual behavior I noticed:
the window decoration went from grey to blue and slightly changed size, then become normal again.

-- 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 0x7f0c8c857900 (LWP 2090))]

Thread 2 (Thread 0x7f0c79970700 (LWP 2106)):
#0  pthread_cond_wait@@GLIBC_2.3.2 () at ../nptl/sysdeps/unix/sysv/linux/x86_64/pthread_cond_wait.S:185
#1  0x00000030e2d8ef2b in QTWTF::TCMalloc_PageHeap::scavengerThread (this=0x30e308df00 <QTWTF::pageheap_memory>) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:2359
#2  0x00000030e2d8ef69 in QTWTF::TCMalloc_PageHeap::runScavengerThread (context=<optimized out>) at ../3rdparty/javascriptcore/JavaScriptCore/wtf/FastMalloc.cpp:1464
#3  0x00000030c1c07f33 in start_thread (arg=0x7f0c79970700) at pthread_create.c:309
#4  0x00000030c18f4ded in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 1 (Thread 0x7f0c8c857900 (LWP 2090)):
[KCrash Handler]
#5  begin (this=0x994) at ../../src/corelib/tools/qlist.h:101
#6  contains (t=@0x7fffee3251c8: 0x32c8fd0, this=0x994) at ../../src/corelib/tools/qlist.h:874
#7  QActionGroup::addAction (this=0x34407a0, a=a@entry=0x32c8fd0) at kernel/qactiongroup.cpp:180
#8  0x000000350a8a5e8f in KWin::UserActionsMenu::activityPopupAboutToShow (this=0x2782770) at /usr/src/debug/kde-workspace-4.11.9/kwin/useractions.cpp:723
#9  0x00000030c999b938 in QMetaObject::activate (sender=sender@entry=0x381b850, m=m@entry=0x3c6c2b2c60 <QMenu::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3567
#10 0x0000003c6bc106d0 in QMenu::aboutToShow (this=this@entry=0x381b850) at .moc/release-shared/moc_qmenu.cpp:164
#11 0x0000003c6bc138d0 in QMenu::popup (this=0x381b850, p=..., atAction=atAction@entry=0x0) at widgets/qmenu.cpp:1843
#12 0x0000003c6bc14fe3 in QMenu::internalDelayedPopup (this=this@entry=0x362dcf0) at widgets/qmenu.cpp:3063
#13 0x0000003c6bc16b24 in QMenu::timerEvent (this=0x362dcf0, e=<optimized out>) at widgets/qmenu.cpp:2923
#14 0x00000030c999fce1 in QObject::event (this=0x362dcf0, e=<optimized out>) at kernel/qobject.cpp:1184
#15 0x0000003c6b81de33 in QWidget::event (this=this@entry=0x362dcf0, event=event@entry=0x7fffee325af0) at kernel/qwidget.cpp:8859
#16 0x0000003c6bc1932b in QMenu::event (this=0x362dcf0, e=0x7fffee325af0) at widgets/qmenu.cpp:2480
#17 0x0000003c6b7caebc in QApplicationPrivate::notify_helper (this=0x25c5230, receiver=0x362dcf0, e=0x7fffee325af0) at kernel/qapplication.cpp:4565
#18 0x0000003c6b7d1825 in QApplication::notify (this=0x7fffee326be0, receiver=0x362dcf0, e=0x7fffee325af0) at kernel/qapplication.cpp:4351
#19 0x00000032e584ab0a in KApplication::notify(QObject*, QEvent*) () from /lib64/libkdeui.so.5
#20 0x00000030c9986ebd in QCoreApplication::notifyInternal (this=0x7fffee326be0, receiver=0x362dcf0, event=event@entry=0x7fffee325af0) at kernel/qcoreapplication.cpp:953
#21 0x00000030c99b8713 in sendEvent (event=0x7fffee325af0, receiver=<optimized out>) at kernel/qcoreapplication.h:231
#22 QTimerInfoList::activateTimers (this=0x25c5cf8) at kernel/qeventdispatcher_unix.cpp:621
#23 0x00000030c99b8790 in QEventDispatcherUNIX::activateTimers (this=this@entry=0x256eca0) at kernel/qeventdispatcher_unix.cpp:878
#24 0x00000030c99b9178 in QEventDispatcherUNIX::processEvents (this=this@entry=0x256eca0, flags=...) at kernel/qeventdispatcher_unix.cpp:940
#25 0x0000003c6b86d6d6 in QEventDispatcherX11::processEvents (this=0x256eca0, flags=...) at kernel/qeventdispatcher_x11.cpp:152
#26 0x00000030c998595f in QEventLoop::processEvents (this=this@entry=0x7fffee325e50, flags=...) at kernel/qeventloop.cpp:149
#27 0x00000030c9985cad in QEventLoop::exec (this=this@entry=0x7fffee325e50, flags=...) at kernel/qeventloop.cpp:204
#28 0x0000003c6bc17f77 in QMenu::exec (this=<optimized out>, p=..., action=action@entry=0x0) at widgets/qmenu.cpp:2124
#29 0x000000350a8a2552 in KWin::UserActionsMenu::show (this=0x2782770, pos=..., cl=...) at /usr/src/debug/kde-workspace-4.11.9/kwin/useractions.cpp:167
#30 0x000000350a8a2639 in KWin::Workspace::showWindowMenu (this=0x2782500, pos=..., cl=0x3172300) at /usr/src/debug/kde-workspace-4.11.9/kwin/useractions.cpp:1827
#31 0x000000350a896902 in KWin::Bridge::showWindowMenu (this=0x315ccf0, p=..., id=<optimized out>) at /usr/src/debug/kde-workspace-4.11.9/kwin/bridge.cpp:110
#32 0x00007f0c7bde297e in Oxygen::Client::mousePressEvent (this=0x3171ec0, event=0x7fffee326450) at /usr/src/debug/kde-workspace-4.11.9/kwin/clients/oxygen/oxygenclient.cpp:1669
#33 0x00007f0c7bdec59a in Oxygen::Client::eventFilter (this=0x3171ec0, object=0x37987c0, event=0x7fffee326450) at /usr/src/debug/kde-workspace-4.11.9/kwin/clients/oxygen/oxygenclient.cpp:1358
#34 0x00000030c9987026 in QCoreApplicationPrivate::sendThroughObjectEventFilters (this=<optimized out>, receiver=0x37987c0, event=0x7fffee326450) at kernel/qcoreapplication.cpp:1063
#35 0x0000003c6b7cae9c in QApplicationPrivate::notify_helper (this=0x25c5230, receiver=0x37987c0, e=0x7fffee326450) at kernel/qapplication.cpp:4561
#36 0x0000003c6b7d1961 in QApplication::notify (this=<optimized out>, receiver=0x37987c0, e=0x7fffee326450) at kernel/qapplication.cpp:4108
#37 0x00000032e584ab0a in KApplication::notify(QObject*, QEvent*) () from /lib64/libkdeui.so.5
#38 0x00000030c9986ebd in QCoreApplication::notifyInternal (this=0x7fffee326be0, receiver=0x37987c0, event=0x7fffee326450) at kernel/qcoreapplication.cpp:953
#39 0x0000003c6b7d10d7 in QApplicationPrivate::sendMouseEvent (receiver=receiver@entry=0x37987c0, event=event@entry=0x7fffee326450, alienWidget=alienWidget@entry=0x0, nativeWidget=nativeWidget@entry=0x37987c0, buttonDown=buttonDown@entry=0x3c6c2df278 <qt_button_down>, lastMouseReceiver=..., spontaneous=spontaneous@entry=true) at ../../src/corelib/kernel/qcoreapplication.h:231
#40 0x0000003c6b8467ab in QETWidget::translateMouseEvent (this=this@entry=0x37987c0, event=event@entry=0x7fffee3267d0) at kernel/qapplication_x11.cpp:4540
#41 0x0000003c6b84521c in QApplication::x11ProcessEvent (this=0x7fffee326be0, event=event@entry=0x7fffee3267d0) at kernel/qapplication_x11.cpp:3663
#42 0x0000003c6b86d670 in QEventDispatcherX11::processEvents (this=0x256eca0, flags=...) at kernel/qeventdispatcher_x11.cpp:132
#43 0x00000030c998595f in QEventLoop::processEvents (this=this@entry=0x7fffee326a30, flags=...) at kernel/qeventloop.cpp:149
#44 0x00000030c9985cad in QEventLoop::exec (this=this@entry=0x7fffee326a30, flags=...) at kernel/qeventloop.cpp:204
#45 0x00000030c998b399 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1225
#46 0x0000003c6b7c952c in QApplication::exec () at kernel/qapplication.cpp:3823
#47 0x000000350a87e4c1 in kdemain (argc=3, argv=0x7fffee326d38) at /usr/src/debug/kde-workspace-4.11.9/kwin/main.cpp:597
#48 0x00000030c1821d65 in __libc_start_main (main=0x4009d0 <main(int, char**)>, argc=3, argv=0x7fffee326d38, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffee326d28) at libc-start.c:285
#49 0x0000000000400a01 in _start ()

Possible duplicates by query: bug 334152.

Reported using DrKonqi