Application: systemsettings5 (5.11.4)

Qt Version: 5.9.3
Frameworks Version: 5.40.0
Operating System: Linux 4.14.4-1-ARCH x86_64
Distribution (Platform): Archlinux Packages

-- Information about the crash:
Change a font setting. Click apply - crash. Repeat.
NB: Actual font display does change with apply.

The crash can be reproduced every time.

-- Backtrace:
Application: System Settings (systemsettings5), signal: Segmentation fault
Using host libthread_db library "/usr/lib/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fa080b71800 (LWP 2202))]

Thread 5 (Thread 0x7fa0517c2700 (LWP 2207)):
#0  0x00007fa0763995f9 in g_mutex_lock () at /usr/lib/libglib-2.0.so.0
#1  0x00007fa076371e96 in  () at /usr/lib/libglib-2.0.so.0
#2  0x00007fa076371fae in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#3  0x00007fa07d0f9204 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#4  0x00007fa07d09c99b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#5  0x00007fa07ceb527e in QThread::exec() () at /usr/lib/libQt5Core.so.5
#6  0x00007fa07af59cf9 in  () at /usr/lib/libQt5Qml.so.5
#7  0x00007fa07ceba1cb in  () at /usr/lib/libQt5Core.so.5
#8  0x00007fa07857108a in start_thread () at /usr/lib/libpthread.so.0
#9  0x00007fa07c7c542f in clone () at /usr/lib/libc.so.6

Thread 4 (Thread 0x7fa059bdc700 (LWP 2206)):
#0  0x00007fa07c7baf2b in poll () at /usr/lib/libc.so.6
#1  0x00007fa076371ed3 in  () at /usr/lib/libglib-2.0.so.0
#2  0x00007fa076371fae in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#3  0x00007fa07d0f9204 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#4  0x00007fa07d09c99b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#5  0x00007fa07ceb527e in QThread::exec() () at /usr/lib/libQt5Core.so.5
#6  0x00007fa07af59cf9 in  () at /usr/lib/libQt5Qml.so.5
#7  0x00007fa07ceba1cb in  () at /usr/lib/libQt5Core.so.5
#8  0x00007fa07857108a in start_thread () at /usr/lib/libpthread.so.0
#9  0x00007fa07c7c542f in clone () at /usr/lib/libc.so.6

Thread 3 (Thread 0x7fa06452b700 (LWP 2204)):
#0  0x00007fa07c7baf2b in poll () at /usr/lib/libc.so.6
#1  0x00007fa076371ed3 in  () at /usr/lib/libglib-2.0.so.0
#2  0x00007fa076371fae in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#3  0x00007fa07d0f9204 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#4  0x00007fa07d09c99b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#5  0x00007fa07ceb527e in QThread::exec() () at /usr/lib/libQt5Core.so.5
#6  0x00007fa07d514376 in  () at /usr/lib/libQt5DBus.so.5
#7  0x00007fa07ceba1cb in  () at /usr/lib/libQt5Core.so.5
#8  0x00007fa07857108a in start_thread () at /usr/lib/libpthread.so.0
#9  0x00007fa07c7c542f in clone () at /usr/lib/libc.so.6

Thread 2 (Thread 0x7fa06d7db700 (LWP 2203)):
#0  0x00007fa07c7baf2b in poll () at /usr/lib/libc.so.6
#1  0x00007fa078df48e0 in  () at /usr/lib/libxcb.so.1
#2  0x00007fa078df6679 in xcb_wait_for_event () at /usr/lib/libxcb.so.1
#3  0x00007fa07037890a in  () at /usr/lib/libQt5XcbQpa.so.5
#4  0x00007fa07ceba1cb in  () at /usr/lib/libQt5Core.so.5
#5  0x00007fa07857108a in start_thread () at /usr/lib/libpthread.so.0
#6  0x00007fa07c7c542f in clone () at /usr/lib/libc.so.6

Thread 1 (Thread 0x7fa080b71800 (LWP 2202)):
[KCrash Handler]
#5  0x00007fa041b848f4 in  () at /usr/lib/libQtGui.so.4
#6  0x00007fa0809be51a in call_init.part () at /lib64/ld-linux-x86-64.so.2
#7  0x00007fa0809be626 in _dl_init () at /lib64/ld-linux-x86-64.so.2
#8  0x00007fa0809c2afe in dl_open_worker () at /lib64/ld-linux-x86-64.so.2
#9  0x00007fa07c8010f4 in _dl_catch_error () at /usr/lib/libc.so.6
#10 0x00007fa0809c231a in _dl_open () at /lib64/ld-linux-x86-64.so.2
#11 0x00007fa076624e86 in  () at /usr/lib/libdl.so.2
#12 0x00007fa07c8010f4 in _dl_catch_error () at /usr/lib/libc.so.6
#13 0x00007fa076625587 in  () at /usr/lib/libdl.so.2
#14 0x00007fa076624f22 in dlopen () at /usr/lib/libdl.so.2
#15 0x00007fa047ba0ef1 in  () at /usr/lib/libvlccore.so.8
#16 0x00007fa047b84a1a in  () at /usr/lib/libvlccore.so.8
#17 0x00007fa047b85012 in  () at /usr/lib/libvlccore.so.8
#18 0x00007fa047b85762 in  () at /usr/lib/libvlccore.so.8
#19 0x00007fa047b85b7b in  () at /usr/lib/libvlccore.so.8
#20 0x00007fa047b0922f in libvlc_InternalInit () at /usr/lib/libvlccore.so.8
#21 0x00007fa0478db183 in libvlc_new () at /usr/lib/libvlc.so.5
#22 0x00007fa047e3e051 in  () at /usr/lib/qt5/plugins/phonon4qt5_backend/phonon_vlc.so
#23 0x00007fa047e118f3 in  () at /usr/lib/qt5/plugins/phonon4qt5_backend/phonon_vlc.so
#24 0x00007fa047e427b8 in qt_plugin_instance () at /usr/lib/qt5/plugins/phonon4qt5_backend/phonon_vlc.so
#25 0x00007fa07d080ff7 in QPluginLoader::instance() () at /usr/lib/libQt5Core.so.5
#26 0x00007fa066914380 in  () at /usr/lib/libphonon4qt5.so.4
#27 0x00007fa0669167ec in  () at /usr/lib/libphonon4qt5.so.4
#28 0x00007fa06691719e in  () at /usr/lib/libphonon4qt5.so.4
#29 0x00007fa06691802c in Phonon::Factory::backend(bool) () at /usr/lib/libphonon4qt5.so.4
#30 0x00007fa066918919 in  () at /usr/lib/libphonon4qt5.so.4
#31 0x00007fa06690a4d1 in  () at /usr/lib/libphonon4qt5.so.4
#32 0x00007fa067afcf84 in  () at /usr/lib/libKF5Notifications.so.5
#33 0x00007fa067acf4aa in  () at /usr/lib/libKF5Notifications.so.5
#34 0x00007fa067acc2e6 in KNotification::sendEvent() () at /usr/lib/libKF5Notifications.so.5
#35 0x00007fa07d0ceb72 in QObject::event(QEvent*) () at /usr/lib/libQt5Core.so.5
#36 0x00007fa07ec60f5c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#37 0x00007fa07ec68a36 in QApplication::notify(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#38 0x00007fa07d09e570 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /usr/lib/libQt5Core.so.5
#39 0x00007fa07d0a0dc6 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () at /usr/lib/libQt5Core.so.5
#40 0x00007fa07d0f9bf4 in  () at /usr/lib/libQt5Core.so.5
#41 0x00007fa076370270 in g_main_context_dispatch () at /usr/lib/libglib-2.0.so.0
#42 0x00007fa076371f69 in  () at /usr/lib/libglib-2.0.so.0
#43 0x00007fa076371fae in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#44 0x00007fa07d0f91e1 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#45 0x00007fa07d09c99b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#46 0x00007fa07ee54f9b in QDialog::exec() () at /usr/lib/libQt5Widgets.so.5
#47 0x00007fa07f428c8b in KMessageBox::createKMessageBox(QDialog*, QDialogButtonBox*, QIcon const&, QString const&, QStringList const&, QString const&, bool*, QFlags<KMessageBox::Option>, QString const&, QMessageBox::Icon) () at /usr/lib/libKF5WidgetsAddons.so.5
#48 0x00007fa07f428e9d in KMessageBox::createKMessageBox(QDialog*, QDialogButtonBox*, QMessageBox::Icon, QString const&, QStringList const&, QString const&, bool*, QFlags<KMessageBox::Option>, QString const&) () at /usr/lib/libKF5WidgetsAddons.so.5
#49 0x00007fa07f42f200 in KMessageBox::informationList(QWidget*, QString const&, QStringList const&, QString const&, QString const&, QFlags<KMessageBox::Option>) () at /usr/lib/libKF5WidgetsAddons.so.5
#50 0x00007fa07f42f35a in KMessageBox::information(QWidget*, QString const&, QString const&, QString const&, QFlags<KMessageBox::Option>) () at /usr/lib/libKF5WidgetsAddons.so.5
#51 0x00007fa04932c394 in  () at /usr/lib/qt/plugins/kcm_fonts.so
#52 0x00007fa080565408 in KCModuleProxy::save() () at /usr/lib/libKF5KCMUtils.so.5
#53 0x00007fa0807a5682 in ModuleView::moduleSave(KCModuleProxy*) () at /usr/lib/libsystemsettingsview.so.3
#54 0x00007fa0807a92eb in  () at /usr/lib/libsystemsettingsview.so.3
#55 0x00007fa07d0ce126 in QMetaObject::activate(QObject*, int, int, void**) () at /usr/lib/libQt5Core.so.5
#56 0x00007fa07ed560e3 in QAbstractButton::clicked(bool) () at /usr/lib/libQt5Widgets.so.5
#57 0x00007fa07ed562fc in  () at /usr/lib/libQt5Widgets.so.5
#58 0x00007fa07ed5773c in  () at /usr/lib/libQt5Widgets.so.5
#59 0x00007fa07ed57935 in QAbstractButton::mouseReleaseEvent(QMouseEvent*) () at /usr/lib/libQt5Widgets.so.5
#60 0x00007fa07eca0a98 in QWidget::event(QEvent*) () at /usr/lib/libQt5Widgets.so.5
#61 0x00007fa07ec60f5c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#62 0x00007fa07ec68fb1 in QApplication::notify(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#63 0x00007fa07d09e570 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /usr/lib/libQt5Core.so.5
#64 0x00007fa07ec67f3a in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&, bool) () at /usr/lib/libQt5Widgets.so.5
#65 0x00007fa07ecbbe61 in  () at /usr/lib/libQt5Widgets.so.5
#66 0x00007fa07ecbe5a1 in  () at /usr/lib/libQt5Widgets.so.5
#67 0x00007fa07ec60f5c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#68 0x00007fa07ec68a36 in QApplication::notify(QObject*, QEvent*) () at /usr/lib/libQt5Widgets.so.5
#69 0x00007fa07d09e570 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /usr/lib/libQt5Core.so.5
#70 0x00007fa07e4a23d4 in QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::MouseEvent*) () at /usr/lib/libQt5Gui.so.5
#71 0x00007fa07e4a3f36 in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) () at /usr/lib/libQt5Gui.so.5
#72 0x00007fa07e47b48c in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Gui.so.5
#73 0x00007fa0703dd6b1 in  () at /usr/lib/libQt5XcbQpa.so.5
#74 0x00007fa076370270 in g_main_context_dispatch () at /usr/lib/libglib-2.0.so.0
#75 0x00007fa076371f69 in  () at /usr/lib/libglib-2.0.so.0
#76 0x00007fa076371fae in g_main_context_iteration () at /usr/lib/libglib-2.0.so.0
#77 0x00007fa07d0f91e1 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#78 0x00007fa07d09c99b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/libQt5Core.so.5
#79 0x00007fa07d0a59e8 in QCoreApplication::exec() () at /usr/lib/libQt5Core.so.5
#80 0x000055b0af98ccca in  ()
#81 0x00007fa07c6eff4a in __libc_start_main () at /usr/lib/libc.so.6
#82 0x000055b0af98cd4a in _start ()

Reported using DrKonqi