Bug 353884

Application: plasmashell (5.4.1)

Qt Version: 5.5.0
Operating System: Linux 4.2.1-1-desktop x86_64
Distribution: "openSUSE Tumbleweed (20151002) (x86_64)"

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

I have a Dell Latitude E6430s connected at work to an external monitor via a docking station.
I removed a panel and added a new default panel. This caused plasma to crash.

- Unusual behavior I noticed:

Recently when connecting to the external screen, the panel moves from the bottom of the laptop screen to bottom of the external one, despite the fact that the former is marked as primary.
If I try to move the panel with "Screen Edge" to the laptop screen, it disappears. After some plug-unplug and/or sleep/awake cicle the panel reappear in the external screen on the top.

This is way I've decided to remove the panel and read it in the place I want it.

If relevant and/or somehow connected. 
I've tried to tinker with "System Settings -> Display and Monitor" to get the panel back to the correct position, but it made things worse:
* if I try to disable the external monitor, it goes black but the windows on that monitor are not moved to the laptop one. If I have the system settings open on the external monitor, I cannot use it anymore.
   xrandr tells that the screen is connected, though. If I try to turn it off and on, nothing happens
* I've tried to set the external to primary and then back, hoping that this would move the panel back, but I ended up with my background and desktop widget disappearing.

On the same machine I have Kubuntu 15.10 and seems to behave correctly with respect to the panel positioning.

-- Backtrace:
Application: Plasma (plasmashell), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fae9b95d8c0 (LWP 1931))]

Thread 8 (Thread 0x7fae84ec6700 (LWP 1934)):
#0  0x00007fae94f4fe7d in poll () at /lib64/libc.so.6
#1  0x00007fae99dc9432 in  () at /usr/lib64/libxcb.so.1
#2  0x00007fae99dcb007 in xcb_wait_for_event () at /usr/lib64/libxcb.so.1
#3  0x00007fae87015e89 in QXcbEventReader::run() (this=0x22f7670) at qxcbconnection.cpp:1214
#4  0x00007fae9563ea9f in QThreadPrivate::start(void*) (arg=0x22f7670) at thread/qthread_unix.cpp:331
#5  0x00007fae947584a4 in start_thread () at /lib64/libpthread.so.0
#6  0x00007fae94f5880d in clone () at /lib64/libc.so.6

Thread 7 (Thread 0x7fae7e20e700 (LWP 1976)):
#0  0x00007fae94f4fe7d in poll () at /lib64/libc.so.6
#1  0x00007fae91657e94 in  () at /usr/lib64/libglib-2.0.so.0
#2  0x00007fae91657f9c in g_main_context_iteration () at /usr/lib64/libglib-2.0.so.0
#3  0x00007fae9586335b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7fae780008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:420
#4  0x00007fae9580d47a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7fae7e20dcf0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#5  0x00007fae95639c6c in QThread::exec() (this=<optimized out>) at thread/qthread.cpp:503
#6  0x00007fae988aa1a5 in  () at /usr/lib64/libQt5Qml.so.5
#7  0x00007fae9563ea9f in QThreadPrivate::start(void*) (arg=0x23d1120) at thread/qthread_unix.cpp:331
#8  0x00007fae947584a4 in start_thread () at /lib64/libpthread.so.0
#9  0x00007fae94f5880d in clone () at /lib64/libc.so.6

Thread 6 (Thread 0x7fae711c8700 (LWP 1991)):
#0  0x00007fae94f4fe7d in poll () at /lib64/libc.so.6
#1  0x00007fae91657e94 in  () at /usr/lib64/libglib-2.0.so.0
#2  0x00007fae91657f9c in g_main_context_iteration () at /usr/lib64/libglib-2.0.so.0
#3  0x00007fae9586335b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7fae6c0008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:420
#4  0x00007fae9580d47a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7fae711c7cf0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#5  0x00007fae95639c6c in QThread::exec() (this=<optimized out>) at thread/qthread.cpp:503
#6  0x00007fae988aa1a5 in  () at /usr/lib64/libQt5Qml.so.5
#7  0x00007fae9563ea9f in QThreadPrivate::start(void*) (arg=0x274dd10) at thread/qthread_unix.cpp:331
#8  0x00007fae947584a4 in start_thread () at /lib64/libpthread.so.0
#9  0x00007fae94f5880d in clone () at /lib64/libc.so.6

Thread 5 (Thread 0x7fae6b5a0700 (LWP 1995)):
#0  0x00007fae94f4be5d in read () at /lib64/libc.so.6
#1  0x00007fae9169a850 in  () at /usr/lib64/libglib-2.0.so.0
#2  0x00007fae916579c4 in g_main_context_check () at /usr/lib64/libglib-2.0.so.0
#3  0x00007fae91657e38 in  () at /usr/lib64/libglib-2.0.so.0
#4  0x00007fae91657f9c in g_main_context_iteration () at /usr/lib64/libglib-2.0.so.0
#5  0x00007fae9586335b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7fae640008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:420
#6  0x00007fae9580d47a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7fae6b59fcf0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#7  0x00007fae95639c6c in QThread::exec() (this=<optimized out>) at thread/qthread.cpp:503
#8  0x00007fae988aa1a5 in  () at /usr/lib64/libQt5Qml.so.5
#9  0x00007fae9563ea9f in QThreadPrivate::start(void*) (arg=0x280b670) at thread/qthread_unix.cpp:331
#10 0x00007fae947584a4 in start_thread () at /lib64/libpthread.so.0
#11 0x00007fae94f5880d in clone () at /lib64/libc.so.6

Thread 4 (Thread 0x7fae69cbf700 (LWP 1998)):
#0  0x00007fae9475e07f in pthread_cond_wait@@GLIBC_2.3.2 () at /lib64/libpthread.so.0
#1  0x00007fae9b03aaa4 in  () at /usr/lib64/libQt5Script.so.5
#2  0x00007fae9b03aae9 in  () at /usr/lib64/libQt5Script.so.5
#3  0x00007fae947584a4 in start_thread () at /lib64/libpthread.so.0
#4  0x00007fae94f5880d in clone () at /lib64/libc.so.6

Thread 3 (Thread 0x7fade250d700 (LWP 2002)):
#0  0x00007fae9169bb30 in g_mutex_lock () at /usr/lib64/libglib-2.0.so.0
#1  0x00007fae9165791c in g_main_context_check () at /usr/lib64/libglib-2.0.so.0
#2  0x00007fae91657e38 in  () at /usr/lib64/libglib-2.0.so.0
#3  0x00007fae91657f9c in g_main_context_iteration () at /usr/lib64/libglib-2.0.so.0
#4  0x00007fae9586335b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7faddc0008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:420
#5  0x00007fae9580d47a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7fade250ccb0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#6  0x00007fae95639c6c in QThread::exec() (this=<optimized out>) at thread/qthread.cpp:503
#7  0x00007fae99427b62 in  () at /usr/lib64/libQt5Quick.so.5
#8  0x00007fae9563ea9f in QThreadPrivate::start(void*) (arg=0x2b65a60) at thread/qthread_unix.cpp:331
#9  0x00007fae947584a4 in start_thread () at /lib64/libpthread.so.0
#10 0x00007fae94f5880d in clone () at /lib64/libc.so.6

Thread 2 (Thread 0x7fadd193a700 (LWP 2301)):
#0  0x00007fae91656ee3 in g_main_context_acquire () at /usr/lib64/libglib-2.0.so.0
#1  0x00007fae91657d65 in  () at /usr/lib64/libglib-2.0.so.0
#2  0x00007fae91657f9c in g_main_context_iteration () at /usr/lib64/libglib-2.0.so.0
#3  0x00007fae9586335b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7fadcc0008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:420
#4  0x00007fae9580d47a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7fadd1939cd0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#5  0x00007fae95639c6c in QThread::exec() (this=<optimized out>) at thread/qthread.cpp:503
#6  0x00007fadd3e4ab77 in KCupsConnection::run() () at /usr/lib64/libkcupslib.so
#7  0x00007fae9563ea9f in QThreadPrivate::start(void*) (arg=0x5092c00) at thread/qthread_unix.cpp:331
#8  0x00007fae947584a4 in start_thread () at /lib64/libpthread.so.0
#9  0x00007fae94f5880d in clone () at /lib64/libc.so.6

Thread 1 (Thread 0x7fae9b95d8c0 (LWP 1931)):
[KCrash Handler]
#6  0x00007fae9583ea23 in QObjectPrivate::addConnection(int, QObjectPrivate::Connection*) (this=0x614300080000401b, signal=signal@entry=3, c=0x49d9f40) at kernel/qobject.cpp:369
#7  0x00007fae9583fe06 in QObjectPrivate::connectImpl(QObject const*, int, QObject const*, void**, QtPrivate::QSlotObjectBase*, Qt::ConnectionType, int const*, QMetaObject const*) (sender=sender@entry=0x4c33020, signal_index=3, receiver=receiver@entry=0x6f4d630, slot=slot@entry=0x7fff56cbc530, slotObj=slotObj@entry=0x7c0de20, type=Qt::AutoConnection, types=0x0, senderMetaObject=0x7fadd9aeda60 <QPulseAudio::MapBaseQObject::staticMetaObject>) at kernel/qobject.cpp:4703
#8  0x00007fae9584022d in QObject::connectImpl(QObject const*, void**, QObject const*, void**, QtPrivate::QSlotObjectBase*, Qt::ConnectionType, int const*, QMetaObject const*) (sender=0x4c33020, signal=<optimized out>, receiver=0x6f4d630, slot=0x7fff56cbc530, slotObj=0x7c0de20, type=Qt::AutoConnection, types=0x0, senderMetaObject=0x7fadd9aeda60 <QPulseAudio::MapBaseQObject::staticMetaObject>) at kernel/qobject.cpp:4646
#9  0x00007fadd98d68cf in QPulseAudio::AbstractModel::AbstractModel(QPulseAudio::MapBaseQObject const*, QObject*) () at /usr/lib64/libQPulseAudioPrivate.so
#10 0x00007fadd98d91be in QPulseAudio::SinkModel::SinkModel(QObject*) () at /usr/lib64/libQPulseAudioPrivate.so
#11 0x00007fadd9b27b30 in  () at /usr/lib64/qt5/qml/org/kde/plasma/private/volume/libplasma-volume-declarative.so
#12 0x00007fae9884688b in QQmlType::create() const () at /usr/lib64/libQt5Qml.so.5
#13 0x00007fae988a3eb4 in  () at /usr/lib64/libQt5Qml.so.5
#14 0x00007fae988a628b in  () at /usr/lib64/libQt5Qml.so.5
#15 0x00007fae988a64f0 in  () at /usr/lib64/libQt5Qml.so.5
#16 0x00007fae988a2b2a in  () at /usr/lib64/libQt5Qml.so.5
#17 0x00007fae988a346a in  () at /usr/lib64/libQt5Qml.so.5
#18 0x00007fae988a628b in  () at /usr/lib64/libQt5Qml.so.5
#19 0x00007fae988a64f0 in  () at /usr/lib64/libQt5Qml.so.5
#20 0x00007fae988a2b2a in  () at /usr/lib64/libQt5Qml.so.5
#21 0x00007fae988a346a in  () at /usr/lib64/libQt5Qml.so.5
#22 0x00007fae988a628b in  () at /usr/lib64/libQt5Qml.so.5
#23 0x00007fae988a64f0 in  () at /usr/lib64/libQt5Qml.so.5
#24 0x00007fae988a2b2a in  () at /usr/lib64/libQt5Qml.so.5
#25 0x00007fae988a346a in  () at /usr/lib64/libQt5Qml.so.5
#26 0x00007fae988a628b in  () at /usr/lib64/libQt5Qml.so.5
#27 0x00007fae988a64f0 in  () at /usr/lib64/libQt5Qml.so.5
#28 0x00007fae988a2b2a in  () at /usr/lib64/libQt5Qml.so.5
#29 0x00007fae988a346a in  () at /usr/lib64/libQt5Qml.so.5
#30 0x00007fae988a493f in  () at /usr/lib64/libQt5Qml.so.5
#31 0x00007fae98833ca7 in  () at /usr/lib64/libQt5Qml.so.5
#32 0x00007fae988344fc in QQmlIncubationController::incubateFor(int) () at /usr/lib64/libQt5Qml.so.5
#33 0x00007fae999063fc in  () at /usr/lib64/libKF5Declarative.so.5
#34 0x00007fae98834369 in QQmlEnginePrivate::incubate(QQmlIncubator&, QQmlContextData*) () at /usr/lib64/libQt5Qml.so.5
#35 0x00007fae9882fd0c in QQmlComponent::create(QQmlIncubator&, QQmlContext*, QQmlContext*) () at /usr/lib64/libQt5Qml.so.5
#36 0x00007fae998f6e25 in KDeclarative::QmlObject::completeInitialization(QHash<QString, QVariant> const&) () at /usr/lib64/libKF5Declarative.so.5
#37 0x00007fae9b364898 in PlasmaQuick::AppletQuickItem::init() () at /usr/lib64/libKF5PlasmaQuick.so.5
#38 0x00007fae6b5b5b54 in  () at /usr/lib64/qt5/plugins/plasma/scriptengines/plasma_appletscript_declarative.so
#39 0x00007fae6b5b51a9 in  () at /usr/lib64/qt5/plugins/plasma/scriptengines/plasma_appletscript_declarative.so
#40 0x00007fae9583db89 in QObject::event(QEvent*) (this=0x59a4fd0, e=<optimized out>) at kernel/qobject.cpp:1246
#41 0x00007fae994b446b in QQuickItem::event(QEvent*) () at /usr/lib64/libQt5Quick.so.5
#42 0x00007fae6b5b5e06 in  () at /usr/lib64/qt5/plugins/plasma/scriptengines/plasma_appletscript_declarative.so
#43 0x00007fae96b868fc in QApplicationPrivate::notify_helper(QObject*, QEvent*) (this=this@entry=0x22dbf00, receiver=receiver@entry=0x59a4fd0, e=e@entry=0x523b7f0) at kernel/qapplication.cpp:3717
#44 0x00007fae96b8ba06 in QApplication::notify(QObject*, QEvent*) (this=0x7fff56cbe880, receiver=0x59a4fd0, e=0x523b7f0) at kernel/qapplication.cpp:3500
#45 0x00007fae9580fb33 in QCoreApplication::notifyInternal(QObject*, QEvent*) (this=0x7fff56cbe880, receiver=0x59a4fd0, event=event@entry=0x523b7f0) at kernel/qcoreapplication.cpp:965
#46 0x00007fae95811e56 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) (event=0x523b7f0, receiver=<optimized out>) at kernel/qcoreapplication.h:224
#47 0x00007fae95811e56 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) (receiver=receiver@entry=0x0, event_type=event_type@entry=0, data=0x22d16a0) at kernel/qcoreapplication.cpp:1593
#48 0x00007fae95812338 in QCoreApplication::sendPostedEvents(QObject*, int) (receiver=receiver@entry=0x0, event_type=event_type@entry=0) at kernel/qcoreapplication.cpp:1451
#49 0x00007fae95862f33 in postEventSourceDispatch(GSource*, GSourceFunc, gpointer) (s=0x23237d0) at kernel/qeventdispatcher_glib.cpp:271
#50 0x00007fae91657cc7 in g_main_context_dispatch () at /usr/lib64/libglib-2.0.so.0
#51 0x00007fae91657ef8 in  () at /usr/lib64/libglib-2.0.so.0
#52 0x00007fae91657f9c in g_main_context_iteration () at /usr/lib64/libglib-2.0.so.0
#53 0x00007fae9586333f in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x2325df0, flags=...) at kernel/qeventdispatcher_glib.cpp:418
#54 0x00007fae9580d47a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7fff56cbe710, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#55 0x00007fae9581511d in QCoreApplication::exec() () at kernel/qcoreapplication.cpp:1229
#56 0x00007fae95d4b1bc in QGuiApplication::exec() () at kernel/qguiapplication.cpp:1528
#57 0x00007fae96b82fa5 in QApplication::exec() () at kernel/qapplication.cpp:2977
#58 0x00000000004360c0 in main(int, char**) (argc=2, argv=<optimized out>) at /usr/src/debug/plasma-workspace-5.4.1/shell/main.cpp:176

Reported using DrKonqi