Application: plasmashell (5.9.4)

Qt Version: 5.8.0
Frameworks Version: 5.32.0
Operating System: Linux 4.4.59-1-MANJARO x86_64
Distribution: "Manjaro Linux"

-- Information about the crash:
I closed applications, first Qupzilla and then Lazarus Pascal IDE compiled with QT widgetset. Then it crashed and recovered.
Distro is Manjaro with latest updates.

The crash can be reproduced sometimes.

-- Backtrace:
Application: Plasma (plasmashell), signal: Segmentation fault
Using host libthread_db library "/usr/lib/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f3c4bf9f800 (LWP 775))]

Thread 7 (Thread 0x7f3b7ca74700 (LWP 980)):
#0  0x00007f3c4566867d in poll () at /usr/lib/libc.so.6
#1  0x00007f3c4044e7a6 in  () at /usr/lib/libglib-2.0.so.0
#2  0x00007f3c4044e8bc in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#3  0x00007f3c45f8f06b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#4  0x00007f3c45f3889a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#5  0x00007f3c45d5aa73 in QThread::exec() () at /usr/lib/libQt5Core.so.5
#6  0x00007f3b7f4120a7 in KCupsConnection::run() () at /usr/lib/libkcupslib.so
#7  0x00007f3c45d5f6d8 in  () at /usr/lib/libQt5Core.so.5
#8  0x00007f3c44c142e7 in start_thread () at /usr/lib/libpthread.so.0
#9  0x00007f3c4567254f in clone () at /usr/lib/libc.so.6

Thread 6 (Thread 0x7f3b9256f700 (LWP 966)):
#0  0x00007f3c4044e15a in g_main_context_check () at /usr/lib/libglib-2.0.so.0
#1  0x00007f3c4044e744 in  () at /usr/lib/libglib-2.0.so.0
#2  0x00007f3c4044e8bc in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#3  0x00007f3c45f8f06b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#4  0x00007f3c45f3889a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#5  0x00007f3c45d5aa73 in QThread::exec() () at /usr/lib/libQt5Core.so.5
#6  0x00007f3c49a45fd6 in  () at /usr/lib/libQt5Quick.so.5
#7  0x00007f3c45d5f6d8 in  () at /usr/lib/libQt5Core.so.5
#8  0x00007f3c44c142e7 in start_thread () at /usr/lib/libpthread.so.0
#9  0x00007f3c4567254f in clone () at /usr/lib/libc.so.6

Thread 5 (Thread 0x7f3c27bef700 (LWP 916)):
#0  0x00007f3c4567f84b in clock_gettime () at /usr/lib/libc.so.6
#1  0x00007f3c45f8e201 in  () at /usr/lib/libQt5Core.so.5
#2  0x00007f3c45f8c9c9 in QTimerInfoList::updateCurrentTime() () at /usr/lib/libQt5Core.so.5
#3  0x00007f3c45f8cf75 in QTimerInfoList::timerWait(timespec&) () at /usr/lib/libQt5Core.so.5
#4  0x00007f3c45f8e63e in  () at /usr/lib/libQt5Core.so.5
#5  0x00007f3c4044dc8d in g_main_context_prepare () at /usr/lib/libglib-2.0.so.0
#6  0x00007f3c4044e6cb in  () at /usr/lib/libglib-2.0.so.0
#7  0x00007f3c4044e8bc in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#8  0x00007f3c45f8f06b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#9  0x00007f3c45f3889a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#10 0x00007f3c45d5aa73 in QThread::exec() () at /usr/lib/libQt5Core.so.5
#11 0x00007f3c48e92025 in  () at /usr/lib/libQt5Qml.so.5
#12 0x00007f3c45d5f6d8 in  () at /usr/lib/libQt5Core.so.5
#13 0x00007f3c44c142e7 in start_thread () at /usr/lib/libpthread.so.0
#14 0x00007f3c4567254f in clone () at /usr/lib/libc.so.6

Thread 4 (Thread 0x7f3c2cb78700 (LWP 911)):
#0  0x00007f3c44c1a756 in pthread_cond_wait@@GLIBC_2.3.2 () at /usr/lib/libpthread.so.0
#1  0x00007f3c4b739234 in  () at /usr/lib/libQt5Script.so.5
#2  0x00007f3c4b739279 in  () at /usr/lib/libQt5Script.so.5
#3  0x00007f3c44c142e7 in start_thread () at /usr/lib/libpthread.so.0
#4  0x00007f3c4567254f in clone () at /usr/lib/libc.so.6

Thread 3 (Thread 0x7f3c2e5b7700 (LWP 897)):
#0  0x00007f3c40493e64 in g_mutex_unlock () at /usr/lib/libglib-2.0.so.0
#1  0x00007f3c4044e64d in  () at /usr/lib/libglib-2.0.so.0
#2  0x00007f3c4044e8bc in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#3  0x00007f3c45f8f06b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#4  0x00007f3c45f3889a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#5  0x00007f3c45d5aa73 in QThread::exec() () at /usr/lib/libQt5Core.so.5
#6  0x00007f3c48e92025 in  () at /usr/lib/libQt5Qml.so.5
#7  0x00007f3c45d5f6d8 in  () at /usr/lib/libQt5Core.so.5
#8  0x00007f3c44c142e7 in start_thread () at /usr/lib/libpthread.so.0
#9  0x00007f3c4567254f in clone () at /usr/lib/libc.so.6

Thread 2 (Thread 0x7f3c2ffff700 (LWP 848)):
#0  0x00007f3c4566867d in poll () at /usr/lib/libc.so.6
#1  0x00007f3c4044e7a6 in  () at /usr/lib/libglib-2.0.so.0
#2  0x00007f3c4044e8bc in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#3  0x00007f3c45f8f06b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#4  0x00007f3c45f3889a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#5  0x00007f3c45d5aa73 in QThread::exec() () at /usr/lib/libQt5Core.so.5
#6  0x00007f3c46adf125 in  () at /usr/lib/libQt5DBus.so.5
#7  0x00007f3c45d5f6d8 in  () at /usr/lib/libQt5Core.so.5
#8  0x00007f3c44c142e7 in start_thread () at /usr/lib/libpthread.so.0
#9  0x00007f3c4567254f in clone () at /usr/lib/libc.so.6

Thread 1 (Thread 0x7f3c4bf9f800 (LWP 775)):
[KCrash Handler]
#6  0x00007f3c45f00510 in  () at /usr/lib/libQt5Core.so.5
#7  0x00007f3c45f007e9 in  () at /usr/lib/libQt5Core.so.5
#8  0x00007f3c45f083c9 in  () at /usr/lib/libQt5Core.so.5
#9  0x00007f3c45f65d49 in QMetaObject::activate(QObject*, int, int, void**) () at /usr/lib/libQt5Core.so.5
#10 0x00007f3c45fdd484 in QAbstractItemModel::rowsRemoved(QModelIndex const&, int, int, QAbstractItemModel::QPrivateSignal) () at /usr/lib/libQt5Core.so.5
#11 0x00007f3c45ee1d6b in QAbstractItemModel::endRemoveRows() () at /usr/lib/libQt5Core.so.5
#12 0x00007f3b8915e4ab in  () at /usr/lib/libtaskmanager.so.6
#13 0x00007f3b891616f9 in  () at /usr/lib/libtaskmanager.so.6
#14 0x00007f3c45f65d49 in QMetaObject::activate(QObject*, int, int, void**) () at /usr/lib/libQt5Core.so.5
#15 0x00007f3c45fdd414 in QAbstractItemModel::rowsAboutToBeRemoved(QModelIndex const&, int, int, QAbstractItemModel::QPrivateSignal) () at /usr/lib/libQt5Core.so.5
#16 0x00007f3c45ee1613 in QAbstractItemModel::beginRemoveRows(QModelIndex const&, int, int) () at /usr/lib/libQt5Core.so.5
#17 0x00007f3c45f05b15 in  () at /usr/lib/libQt5Core.so.5
#18 0x00007f3c45f05d14 in  () at /usr/lib/libQt5Core.so.5
#19 0x00007f3c45f083a8 in  () at /usr/lib/libQt5Core.so.5
#20 0x00007f3c45f65d49 in QMetaObject::activate(QObject*, int, int, void**) () at /usr/lib/libQt5Core.so.5
#21 0x00007f3c45fdd414 in QAbstractItemModel::rowsAboutToBeRemoved(QModelIndex const&, int, int, QAbstractItemModel::QPrivateSignal) () at /usr/lib/libQt5Core.so.5
#22 0x00007f3c45ee1613 in QAbstractItemModel::beginRemoveRows(QModelIndex const&, int, int) () at /usr/lib/libQt5Core.so.5
#23 0x00007f3b905698e2 in  () at /usr/lib/libKF5ItemModels.so.5
#24 0x00007f3c45f65d49 in QMetaObject::activate(QObject*, int, int, void**) () at /usr/lib/libQt5Core.so.5
#25 0x00007f3c45fdd414 in QAbstractItemModel::rowsAboutToBeRemoved(QModelIndex const&, int, int, QAbstractItemModel::QPrivateSignal) () at /usr/lib/libQt5Core.so.5
#26 0x00007f3c45ee1613 in QAbstractItemModel::beginRemoveRows(QModelIndex const&, int, int) () at /usr/lib/libQt5Core.so.5
#27 0x00007f3c45efb9c0 in  () at /usr/lib/libQt5Core.so.5
#28 0x00007f3c45f65d49 in QMetaObject::activate(QObject*, int, int, void**) () at /usr/lib/libQt5Core.so.5
#29 0x00007f3c45fdd414 in QAbstractItemModel::rowsAboutToBeRemoved(QModelIndex const&, int, int, QAbstractItemModel::QPrivateSignal) () at /usr/lib/libQt5Core.so.5
#30 0x00007f3c45ee1613 in QAbstractItemModel::beginRemoveRows(QModelIndex const&, int, int) () at /usr/lib/libQt5Core.so.5
#31 0x00007f3b8917b181 in TaskManager::XWindowTasksModel::Private::removeWindow(unsigned long long) () at /usr/lib/libtaskmanager.so.6
#32 0x00007f3c45f660be in QMetaObject::activate(QObject*, int, int, void**) () at /usr/lib/libQt5Core.so.5
#33 0x00007f3c489a4742 in KWindowSystem::windowRemoved(unsigned long long) () at /usr/lib/libKF5WindowSystem.so.5
#34 0x00007f3c2e9d7eb6 in  () at /usr/lib/qt/plugins/kf5/org.kde.kwindowsystem.platforms/KF5WindowSystemX11Plugin.so
#35 0x00007f3c4899cd87 in NETRootInfo::update(QFlags<NET::Property>, QFlags<NET::Property2>) () at /usr/lib/libKF5WindowSystem.so.5
#36 0x00007f3c4899e40c in NETRootInfo::event(xcb_generic_event_t*, QFlags<NET::Property>*, QFlags<NET::Property2>*) () at /usr/lib/libKF5WindowSystem.so.5
#37 0x00007f3c4899e732 in NETRootInfo::event(xcb_generic_event_t*, unsigned long*, int) () at /usr/lib/libKF5WindowSystem.so.5
#38 0x00007f3c2e9d7416 in  () at /usr/lib/qt/plugins/kf5/org.kde.kwindowsystem.platforms/KF5WindowSystemX11Plugin.so
#39 0x00007f3c45f3755f in QAbstractEventDispatcher::filterNativeEvent(QByteArray const&, void*, long*) () at /usr/lib/libQt5Core.so.5
#40 0x00007f3c38759974 in QXcbConnection::handleXcbEvent(xcb_generic_event_t*) () at /usr/lib/libQt5XcbQpa.so.5
#41 0x00007f3c3875a655 in QXcbConnection::processXcbEvents() () at /usr/lib/libQt5XcbQpa.so.5
#42 0x00007f3c45f66ba9 in QObject::event(QEvent*) () at /usr/lib/libQt5Core.so.5
#43 0x00007f3c46ea834c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#44 0x00007f3c46eafb61 in QApplication::notify(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#45 0x00007f3c45f3a440 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /usr/lib/libQt5Core.so.5
#46 0x00007f3c45f3cbcd in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () at /usr/lib/libQt5Core.so.5
#47 0x00007f3c45f8ec43 in  () at /usr/lib/libQt5Core.so.5
#48 0x00007f3c4044e5a7 in g_main_context_dispatch () at /usr/lib/libglib-2.0.so.0
#49 0x00007f3c4044e810 in  () at /usr/lib/libglib-2.0.so.0
#50 0x00007f3c4044e8bc in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#51 0x00007f3c45f8f04f in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#52 0x00007f3c45f3889a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#53 0x00007f3c45f40de4 in QCoreApplication::exec() () at /usr/lib/libQt5Core.so.5
#54 0x000000000041ca42 in  ()
#55 0x00007f3c455a6511 in __libc_start_main () at /usr/lib/libc.so.6
#56 0x000000000041cdca in _start ()

Reported using DrKonqi