crash reproducible on neon dev unstable and Arch Linux (plasma 5.12 beta)

(gdb) thread apply all backtrace

Thread 2 (Thread 0x7fffe23b5700 (LWP 17698)):
#0  0x00007ffff3c2870d in poll ()
    at ../sysdeps/unix/syscall-template.S:84
#1  0x00007fffedbc338c in g_main_context_poll (
    priority=2147483647, n_fds=2, fds=0x7fffdc003220, 
    timeout=<optimized out>, context=0x7fffdc000990)
    at /build/glib2.0-prJhLS/glib2.0-2.48.2/./glib/gmain.c:4135
#2  g_main_context_iterate (context=context@entry=0x7fffdc000990, 
    block=block@entry=1, dispatch=dispatch@entry=1, 
    self=<optimized out>)
    at /build/glib2.0-prJhLS/glib2.0-2.48.2/./glib/gmain.c:3835
#3  0x00007fffedbc349c in g_main_context_iteration (
    context=0x7fffdc000990, may_block=may_block@entry=1)
---Type <return> to continue, or q <return> to quit---
    at /build/glib2.0-prJhLS/glib2.0-2.48.2/./glib/gmain.c:3901
#4  0x00007ffff454f6af in QEventDispatcherGlib::processEvents (
    this=0x7fffdc0008c0, flags=...)
    at kernel/qeventdispatcher_glib.cpp:423
#5  0x00007ffff44f7e2a in QEventLoop::exec (
    this=this@entry=0x7fffe23b4cd0, flags=..., flags@entry=...)
    at kernel/qeventloop.cpp:212
#6  0x00007ffff43208f4 in QThread::exec (
    this=this@entry=0x7ffff4c42d40 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread.cpp:515
#7  0x00007ffff49ce315 in QDBusConnectionManager::run (
    this=0x7ffff4c42d40 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at qdbusconnection.cpp:178
#8  0x00007ffff4325709 in QThreadPrivate::start (
---Type <return> to continue, or q <return> to quit---
    arg=0x7ffff4c42d40 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread_unix.cpp:368
#9  0x00007fffefa4c6ba in start_thread (arg=0x7fffe23b5700)
    at pthread_create.c:333
#10 0x00007ffff3c343dd in clone ()
    at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7ffff7f288c0 (LWP 17694)):
#0  0x0000000000000031 in ?? ()
#1  0x00007fffd29d953e in qDeleteAll<QList<SearchProvider*>::const_iterator> (end=..., begin=...)
    at /usr/include/x86_64-linux-gnu/qt5/QtCore/qalgorithms.h:320
#2  qDeleteAll<QList<SearchProvider*> > (c=...)
    at /usr/include/x86_64-linux-gnu/qt5/QtCore/qalgorithms.h:328
---Type <return> to continue, or q <return> to quit---
#3  ProvidersModel::~ProvidersModel (this=0xab7260, 
    __in_chrg=<optimized out>)
    at /workspace/build/src/urifilters/ikws/ikwsopts.cpp:43
#4  0x00007fffd29d95a9 in ProvidersModel::~ProvidersModel (
    this=0xab7260, __in_chrg=<optimized out>)
    at /workspace/build/src/urifilters/ikws/ikwsopts.cpp:44
#5  0x00007ffff4523d63 in QObjectPrivate::deleteChildren (
    this=this@entry=0xb4cbf0) at kernel/qobject.cpp:1992
#6  0x00007ffff6119624 in QWidget::~QWidget (this=0xabef50, 
    __in_chrg=<optimized out>) at kernel/qwidget.cpp:1709
#7  0x00007ffff6fba5ad in KCModule::~KCModule (this=0xabef50, 
    __in_chrg=<optimized out>)
    at /workspace/build/src/kcmodule.cpp:178
#8  0x00007fffd29e548d in FilterOptions::~FilterOptions (
---Type <return> to continue, or q <return> to quit---
    this=0xabef50, __in_chrg=<optimized out>)
    at /workspace/build/obj-x86_64-linux-gnu/src/urifilters/ikws/../../../../src/urifilters/ikws/ikwsopts.h:35
#9  FilterOptions::~FilterOptions (this=0xabef50, 
    __in_chrg=<optimized out>)
    at /workspace/build/obj-x86_64-linux-gnu/src/urifilters/ikws/../../../../src/urifilters/ikws/ikwsopts.h:35
#10 0x00007fffd2e2c03e in qDeleteAll<QList<KCModule*>::const_iterator> (end=..., begin=...)
    at /usr/include/x86_64-linux-gnu/qt5/QtCore/qalgorithms.h:320
#11 qDeleteAll<QList<KCModule*> > (c=...)
    at /usr/include/x86_64-linux-gnu/qt5/QtCore/qalgorithms.h:328
#12 KURIFilterModule::~KURIFilterModule (this=0xab2ca0, 
    __in_chrg=<optimized out>)
---Type <return> to continue, or q <return> to quit---
    at /workspace/build/src/kcms/webshortcuts/main.cpp:124
#13 0x00007fffd2e2c089 in KURIFilterModule::~KURIFilterModule (
    this=0xab2ca0, __in_chrg=<optimized out>)
    at /workspace/build/src/kcms/webshortcuts/main.cpp:125
#14 0x00007ffff79939f4 in KCModuleProxy::deleteClient (
    this=this@entry=0xaca350)
    at /workspace/build/src/kcmoduleproxy.cpp:179
#15 0x00007ffff7993dba in KCModuleProxy::~KCModuleProxy (
    this=0xaca350, __in_chrg=<optimized out>)
    at /workspace/build/src/kcmoduleproxy.cpp:170
#16 0x00007ffff7993f59 in KCModuleProxy::~KCModuleProxy (
    this=0xaca350, __in_chrg=<optimized out>)
    at /workspace/build/src/kcmoduleproxy.cpp:174
#17 0x00007ffff4523d63 in QObjectPrivate::deleteChildren (
---Type <return> to continue, or q <return> to quit---
    this=this@entry=0xac5b50) at kernel/qobject.cpp:1992
#18 0x00007ffff6119624 in QWidget::~QWidget (this=0xac57f0, 
    __in_chrg=<optimized out>) at kernel/qwidget.cpp:1709
#19 0x00007ffff6119869 in QWidget::~QWidget (this=0xac57f0, 
    __in_chrg=<optimized out>) at kernel/qwidget.cpp:1733
#20 0x00007ffff4523d63 in QObjectPrivate::deleteChildren (
    this=this@entry=0xac58b0) at kernel/qobject.cpp:1992
#21 0x00007ffff6119624 in QWidget::~QWidget (this=0xac5830, 
    __in_chrg=<optimized out>) at kernel/qwidget.cpp:1709
#22 0x00007ffff62767e9 in QScrollArea::~QScrollArea (
    this=0xac5830, __in_chrg=<optimized out>)
    at widgets/qscrollarea.cpp:172
#23 0x00007ffff68d1573 in KPageWidgetItem::Private::~Private (
    this=0xaca2b0, __in_chrg=<optimized out>)
---Type <return> to continue, or q <return> to quit---
    at /workspace/build/src/kpagewidgetmodel.cpp:42
#24 KPageWidgetItem::~KPageWidgetItem (this=0xac9f90, 
    __in_chrg=<optimized out>)
    at /workspace/build/src/kpagewidgetmodel.cpp:88
#25 0x00007ffff68d1649 in KPageWidgetItem::~KPageWidgetItem (
    this=0xac9f90, __in_chrg=<optimized out>)
    at /workspace/build/src/kpagewidgetmodel.cpp:89
#26 0x00007ffff68d209b in PageItem::~PageItem (this=0xac46e0, 
    __in_chrg=<optimized out>)
    at /workspace/build/src/kpagewidgetmodel.cpp:178
#27 0x00007ffff68d2ce0 in KPageWidgetModel::removePage (
    this=0x985140, item=<optimized out>)
    at /workspace/build/src/kpagewidgetmodel.cpp:539
#28 0x00007ffff68d10c7 in KPageWidget::removePage (
---Type <return> to continue, or q <return> to quit---
    this=<optimized out>, item=<optimized out>)
    at /workspace/build/src/kpagewidget.cpp:120
#29 0x00007ffff7bcf205 in ModuleView::closeModules (this=0x971e30)
    at /workspace/build/core/ModuleView.cpp:277
#30 0x00007fffd5fe435e in IconMode::backToOverview (this=0x954f20)
    at /workspace/build/icons/IconMode.cpp:156
#31 0x00007ffff4526279 in QMetaObject::activate (
    sender=sender@entry=0x948e50, signalOffset=<optimized out>, 
    local_signal_index=local_signal_index@entry=1, 
    argv=argv@entry=0x7fffffffd050) at kernel/qobject.cpp:3766
#32 0x00007ffff4526b87 in QMetaObject::activate (
    sender=sender@entry=0x948e50, 
    m=m@entry=0x7ffff67b1e00 <QAction::staticMetaObject>, 
    local_signal_index=local_signal_index@entry=1, 
---Type <return> to continue, or q <return> to quit---
    argv=argv@entry=0x7fffffffd050) at kernel/qobject.cpp:3628
#33 0x00007ffff60d86a2 in QAction::triggered (
    this=this@entry=0x948e50, _t1=false)
    at .moc/moc_qaction.cpp:370
#34 0x00007ffff60dadb0 in QAction::activate (this=0x948e50, 
    event=<optimized out>) at kernel/qaction.cpp:1165
#35 0x00007ffff61d9210 in QAbstractButtonPrivate::click (
    this=0xa3a680) at widgets/qabstractbutton.cpp:397
#36 0x00007ffff61d9344 in QAbstractButton::mouseReleaseEvent (
    this=0xa3a640, e=0x7fffffffd540)
    at widgets/qabstractbutton.cpp:1010
#37 0x00007ffff62b35ca in QToolButton::mouseReleaseEvent (
    this=<optimized out>, e=<optimized out>)
    at widgets/qtoolbutton.cpp:619
---Type <return> to continue, or q <return> to quit---
#38 0x00007ffff611db08 in QWidget::event (this=0xa3a640, 
    event=0x7fffffffd540) at kernel/qwidget.cpp:9200
#39 0x00007ffff61d9d11 in QAbstractButton::event (
    this=this@entry=0xa3a640, e=e@entry=0x7fffffffd540)
    at widgets/qabstractbutton.cpp:968
#40 0x00007ffff62b36a9 in QToolButton::event (this=0xa3a640, 
    event=0x7fffffffd540) at widgets/qtoolbutton.cpp:982
#41 0x00007ffff60deb9c in QApplicationPrivate::notify_helper (
    this=<optimized out>, receiver=0xa3a640, e=0x7fffffffd540)
    at kernel/qapplication.cpp:3722
#42 0x00007ffff60e71cb in QApplication::notify (
    this=<optimized out>, receiver=0xa3a640, e=0x7fffffffd540)
    at kernel/qapplication.cpp:3198
#43 0x00007ffff44f9df8 in QCoreApplication::notifyInternal2 (
---Type <return> to continue, or q <return> to quit---
    receiver=receiver@entry=0xa3a640, 
    event=event@entry=0x7fffffffd540)
    at kernel/qcoreapplication.cpp:1018
#44 0x00007ffff60e5b6f in QCoreApplication::sendEvent (
    event=<optimized out>, receiver=<optimized out>)
    at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:233
#45 QApplicationPrivate::sendMouseEvent (
    receiver=receiver@entry=0xa3a640, 
    event=event@entry=0x7fffffffd540, 
    alienWidget=alienWidget@entry=0xa3a640, 
    nativeWidget=0x6e8360, 
    buttonDown=buttonDown@entry=0x7ffff67e0820 <qt_button_down>, 
    lastMouseReceiver=..., spontaneous=true)
---Type <return> to continue, or q <return> to quit---
    at kernel/qapplication.cpp:2704
#46 0x00007ffff6137b06 in QWidgetWindow::handleMouseEvent (
    this=this@entry=0x800d20, event=event@entry=0x7fffffffd940)
    at kernel/qwidgetwindow.cpp:622
#47 0x00007ffff613a563 in QWidgetWindow::event (this=0x800d20, 
    event=0x7fffffffd940) at kernel/qwidgetwindow.cpp:243
#48 0x00007ffff60deb9c in QApplicationPrivate::notify_helper (
    this=<optimized out>, receiver=0x800d20, e=0x7fffffffd940)
    at kernel/qapplication.cpp:3722
#49 0x00007ffff60e65a7 in QApplication::notify (
    this=0x7fffffffde10, receiver=0x800d20, e=0x7fffffffd940)
    at kernel/qapplication.cpp:3481
#50 0x00007ffff44f9df8 in QCoreApplication::notifyInternal2 (
    receiver=receiver@entry=0x800d20, 
---Type <return> to continue, or q <return> to quit---
    event=event@entry=0x7fffffffd940)
    at kernel/qcoreapplication.cpp:1018
#51 0x00007ffff5970860 in QCoreApplication::sendSpontaneousEvent (
    event=0x7fffffffd940, receiver=0x800d20)
    at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:236
#52 QGuiApplicationPrivate::processMouseEvent (e=0xbc8480)
    at kernel/qguiapplication.cpp:1949
#53 0x00007ffff59727c5 in QGuiApplicationPrivate::processWindowSystemEvent (e=e@entry=0xbc8480) at kernel/qguiapplication.cpp:1733
#54 0x00007ffff594c81b in QWindowSystemInterface::sendWindowSystemEvents (flags=...) at kernel/qwindowsysteminterface.cpp:939
#55 0x00007fffe70e5570 in userEventSourceDispatch(_GSource*, int (*)(void*), void*) ()
---Type <return> to continue, or q <return> to quit---
   from /usr/lib/x86_64-linux-gnu/libQt5WaylandClient.so.5
#56 0x00007fffedbc3197 in g_main_dispatch (context=0x682d10)
    at /build/glib2.0-prJhLS/glib2.0-2.48.2/./glib/gmain.c:3154
#57 g_main_context_dispatch (context=context@entry=0x682d10)
    at /build/glib2.0-prJhLS/glib2.0-2.48.2/./glib/gmain.c:3769
#58 0x00007fffedbc33f0 in g_main_context_iterate (
    context=context@entry=0x682d10, block=block@entry=1, 
    dispatch=dispatch@entry=1, self=<optimized out>)
    at /build/glib2.0-prJhLS/glib2.0-2.48.2/./glib/gmain.c:3840
#59 0x00007fffedbc349c in g_main_context_iteration (
    context=0x682d10, may_block=may_block@entry=1)
    at /build/glib2.0-prJhLS/glib2.0-2.48.2/./glib/gmain.c:3901
#60 0x00007ffff454f6af in QEventDispatcherGlib::processEvents (
    this=0x6c0df0, flags=...)
---Type <return> to continue, or q <return> to quit---
    at kernel/qeventdispatcher_glib.cpp:423
#61 0x00007ffff44f7e2a in QEventLoop::exec (
    this=this@entry=0x7fffffffdcf0, flags=..., flags@entry=...)
    at kernel/qeventloop.cpp:212
#62 0x00007ffff4500d64 in QCoreApplication::exec ()
    at kernel/qcoreapplication.cpp:1291
#63 0x00007ffff596820c in QGuiApplication::exec ()
    at kernel/qguiapplication.cpp:1679
#64 0x00007ffff60deaf5 in QApplication::exec ()
    at kernel/qapplication.cpp:2910
#65 0x000000000040b689 in main (argc=1, argv=<optimized out>)
    at /workspace/build/app/main.cpp:65