Application: plasma-desktop (4.11.2)
KDE Platform Version: 4.11.2
Qt Version: 4.8.5
Operating System: Linux 3.11.6-200.fc19.x86_64 x86_64
Distribution: "Fedora release 19 (Schrödinger’s Cat)"

-- Information about the crash:
this problem comes from the kde default taskbar plasmoid created by Eike Hein.
--
Here is a java program, it will take a few time to close.
Now I close it by right click it's icon in the taskbar.
when the program is cleaning itself.
I right click it's taskbar icon and try to close it again.
between the click of program's icon and "close" menu item, this program ended successfully.
then plasma-desktop crashed

The crash can be reproduced every time.

-- Backtrace:
Application: Plasma 桌面外壳 (plasma-desktop), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f3064ab88c0 (LWP 2250))]

Thread 3 (Thread 0x7f305272e700 (LWP 2253)):
#0  0x0000003830a0b575 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib64/libpthread.so.0
#1  0x00000038529860bb in QTWTF::TCMalloc_PageHeap::scavengerThread() () from /lib64/libQtScript.so.4
#2  0x00000038529860f9 in QTWTF::TCMalloc_PageHeap::runScavengerThread(void*) () from /lib64/libQtScript.so.4
#3  0x0000003830a07c53 in start_thread () from /lib64/libpthread.so.0
#4  0x00000038302f5e1d in clone () from /lib64/libc.so.6

Thread 2 (Thread 0x7f2fc1635700 (LWP 2286)):
#0  0x0000003830a0e0cd in read () from /lib64/libpthread.so.0
#1  0x0000003832a86520 in g_wakeup_acknowledge () from /lib64/libglib-2.0.so.0
#2  0x0000003832a47c1c in g_main_context_check () from /lib64/libglib-2.0.so.0
#3  0x0000003832a4808b in g_main_context_iterate.isra.22 () from /lib64/libglib-2.0.so.0
#4  0x0000003832a481fc in g_main_context_iteration () from /lib64/libglib-2.0.so.0
#5  0x000000383afa7166 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib64/libQtCore.so.4
#6  0x000000383af78ecf in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib64/libQtCore.so.4
#7  0x000000383af791c5 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib64/libQtCore.so.4
#8  0x000000383ae7866f in QThread::exec() () from /lib64/libQtCore.so.4
#9  0x000000383af5a733 in QInotifyFileSystemWatcherEngine::run() () from /lib64/libQtCore.so.4
#10 0x000000383ae7ad0f in QThreadPrivate::start(void*) () from /lib64/libQtCore.so.4
#11 0x0000003830a07c53 in start_thread () from /lib64/libpthread.so.0
#12 0x00000038302f5e1d in clone () from /lib64/libc.so.6

Thread 1 (Thread 0x7f3064ab88c0 (LWP 2250)):
[KCrash Handler]
#5  0x0000003856407af0 in QDeclarativeError::isValid() const () from /lib64/libQtDeclarative.so.4
#6  0x00000038563f0cfb in QDeclarativeBoundSignal::qt_metacall(QMetaObject::Call, int, void**) () from /lib64/libQtDeclarative.so.4
#7  0x000000383af8e172 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /lib64/libQtCore.so.4
#8  0x00007f2fd1343800 in MouseEventListener::sceneEventFilter(QGraphicsItem*, QEvent*) () from /usr/lib64/kde4/imports/org/kde/qtextracomponents/libqtextracomponentsplugin.so
#9  0x000000383d98d425 in QGraphicsScenePrivate::filterDescendantEvent(QGraphicsItem*, QEvent*) () from /lib64/libQtGui.so.4
#10 0x000000383d991a8e in QGraphicsScenePrivate::sendEvent(QGraphicsItem*, QEvent*) () from /lib64/libQtGui.so.4
#11 0x000000383d991f8f in QGraphicsScenePrivate::sendMouseEvent(QGraphicsSceneMouseEvent*) () from /lib64/libQtGui.so.4
#12 0x000000383d99d766 in QGraphicsScenePrivate::mousePressEventHandler(QGraphicsSceneMouseEvent*) () from /lib64/libQtGui.so.4
#13 0x000000383d99dbf9 in QGraphicsScene::mousePressEvent(QGraphicsSceneMouseEvent*) () from /lib64/libQtGui.so.4
#14 0x000000383d9a6a80 in QGraphicsScene::event(QEvent*) () from /lib64/libQtGui.so.4
#15 0x000000383d3c84dc in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /lib64/libQtGui.so.4
#16 0x000000383d3ceaa0 in QApplication::notify(QObject*, QEvent*) () from /lib64/libQtGui.so.4
#17 0x000000383f63fe9a in KApplication::notify(QObject*, QEvent*) () from /lib64/libkdeui.so.5
#18 0x000000383af7a26d in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /lib64/libQtCore.so.4
#19 0x000000383d9bd4af in QGraphicsView::mousePressEvent(QMouseEvent*) () from /lib64/libQtGui.so.4
#20 0x000000383d417991 in QWidget::event(QEvent*) () from /lib64/libQtGui.so.4
#21 0x000000383d7b3cde in QFrame::event(QEvent*) () from /lib64/libQtGui.so.4
#22 0x000000383d9be209 in QGraphicsView::viewportEvent(QEvent*) () from /lib64/libQtGui.so.4
#23 0x000000383af7a3d6 in QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) () from /lib64/libQtCore.so.4
#24 0x000000383d3c84bc in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /lib64/libQtGui.so.4
#25 0x000000383d3cebdd in QApplication::notify(QObject*, QEvent*) () from /lib64/libQtGui.so.4
#26 0x000000383f63fe9a in KApplication::notify(QObject*, QEvent*) () from /lib64/libkdeui.so.5
#27 0x000000383af7a26d in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /lib64/libQtCore.so.4
#28 0x000000383d3ce393 in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&, bool) () from /lib64/libQtGui.so.4
#29 0x000000383d43f92b in QETWidget::translateMouseEvent(_XEvent const*) () from /lib64/libQtGui.so.4
#30 0x000000383d43e39c in QApplication::x11ProcessEvent(_XEvent*) () from /lib64/libQtGui.so.4
#31 0x000000383d464e54 in x11EventSourceDispatch(_GSource*, int (*)(void*), void*) () from /lib64/libQtGui.so.4
#32 0x0000003832a47e06 in g_main_context_dispatch () from /lib64/libglib-2.0.so.0
#33 0x0000003832a48158 in g_main_context_iterate.isra.22 () from /lib64/libglib-2.0.so.0
#34 0x0000003832a481fc in g_main_context_iteration () from /lib64/libglib-2.0.so.0
#35 0x000000383afa7145 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib64/libQtCore.so.4
#36 0x000000383d464fc6 in QGuiEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib64/libQtGui.so.4
#37 0x000000383af78ecf in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib64/libQtCore.so.4
#38 0x000000383af791c5 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib64/libQtCore.so.4
#39 0x000000383af7e45b in QCoreApplication::exec() () from /lib64/libQtCore.so.4
#40 0x0000003848e3c40c in kdemain () from /lib64/libkdeinit4_plasma-desktop.so
#41 0x0000003830221b75 in __libc_start_main () from /lib64/libc.so.6
#42 0x0000000000400971 in _start ()

Reported using DrKonqi