Application: systemsettings5 (5.9.90)

Qt Version: 5.8.0
Frameworks Version: 5.33.0
Operating System: Linux 4.10.6-gentoo x86_64
Distribution: "Gentoo Base System release 2.3"

-- Information about the crash:
When I click on "Configure" button in "Widget Style" settings page, and QtCurve is the selected style, systemsettings5 crashes. With other styles crash does not happen.

QtCurve is from git master.

The crash can be reproduced every time.

-- Backtrace:
Application: System Settings (systemsettings5), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fae934ba840 (LWP 28389))]

Thread 3 (Thread 0x7fae845dd700 (LWP 28392)):
#0  0x00007fae9f3a508d in poll () from /lib64/libc.so.6
#1  0x00007fae9816d346 in g_main_context_iterate.isra () from /usr/lib64/libglib-2.0.so.0
#2  0x00007fae9816d44c in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#3  0x00007faea01e920b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQt5Core.so.5
#4  0x00007faea019ca2a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQt5Core.so.5
#5  0x00007faea000ec8b in QThread::exec() () from /usr/lib64/libQt5Core.so.5
#6  0x00007faea091feb9 in QDBusConnectionManager::run() () from /usr/lib64/libQt5DBus.so.5
#7  0x00007faea0012ecb in QThreadPrivate::start(void*) () from /usr/lib64/libQt5Core.so.5
#8  0x00007fae9c41f374 in start_thread () from /lib64/libpthread.so.0
#9  0x00007fae9f3ae43f in clone () from /lib64/libc.so.6

Thread 2 (Thread 0x7fae90d8e700 (LWP 28391)):
#0  0x00007fae9f3a508d in poll () from /lib64/libc.so.6
#1  0x00007fae9ca5c60f in _xcb_conn_wait () from /usr/lib64/libxcb.so.1
#2  0x00007fae9ca648c9 in xcb_wait_for_event () from /usr/lib64/libxcb.so.1
#3  0x00007fae92cc6b99 in QXcbEventReader::run() () from /usr/lib64/libQt5XcbQpa.so.5
#4  0x00007faea0012ecb in QThreadPrivate::start(void*) () from /usr/lib64/libQt5Core.so.5
#5  0x00007fae9c41f374 in start_thread () from /lib64/libpthread.so.0
#6  0x00007fae9f3ae43f in clone () from /lib64/libc.so.6

Thread 1 (Thread 0x7fae934ba840 (LWP 28389)):
[KCrash Handler]
#6  0x00007faea1191fa4 in QWindow::type() const () from /usr/lib64/libQt5Gui.so.5
#7  0x00007faea1196f72 in QWindow::winId() const () from /usr/lib64/libQt5Gui.so.5
#8  0x00007fae90144fd6 in QDBusMenuBar::unregisterMenuBar() () from /usr/lib64/qt5/plugins/platformthemes/KDEPlasmaPlatformTheme.so
#9  0x00007fae9014559d in QDBusMenuBar::handleReparent(QWindow*) () from /usr/lib64/qt5/plugins/platformthemes/KDEPlasmaPlatformTheme.so
#10 0x00007faea17eca9c in QMenuBarPrivate::handleReparent() () from /usr/lib64/libQt5Widgets.so.5
#11 0x00007faea17ed725 in QMenuBar::eventFilter(QObject*, QEvent*) () from /usr/lib64/libQt5Widgets.so.5
#12 0x00007faea019d7d2 in QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) () from /usr/lib64/libQt5Core.so.5
#13 0x00007faea167d585 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib64/libQt5Widgets.so.5
#14 0x00007faea1684819 in QApplication::notify(QObject*, QEvent*) () from /usr/lib64/libQt5Widgets.so.5
#15 0x00007faea019d99a in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib64/libQt5Core.so.5
#16 0x00007faea16c3256 in QWidget::setParent(QWidget*, QFlags<Qt::WindowType>) () from /usr/lib64/libQt5Widgets.so.5
#17 0x00007faea16c3f9c in QWidget::setParent(QWidget*) () from /usr/lib64/libQt5Widgets.so.5
#18 0x00007faea169fc86 in QLayout::addChildWidget(QWidget*) () from /usr/lib64/libQt5Widgets.so.5
#19 0x00007faea169fcff in QLayout::addWidget(QWidget*) () from /usr/lib64/libQt5Widgets.so.5
#20 0x00007faea17d417c in QMdiSubWindow::setWidget(QWidget*) () from /usr/lib64/libQt5Widgets.so.5
#21 0x00007faea17c8be3 in QMdiArea::addSubWindow(QWidget*, QFlags<Qt::WindowType>) () from /usr/lib64/libQt5Widgets.so.5
#22 0x00007fae7b4cf285 in QtCurveConfig::previewControlPressed() () from /usr/lib64/qt5/plugins/kstyle_qtcurve5_config.so
#23 0x00007fae7b4cf3a9 in QtCurveConfig::setupPreview() () from /usr/lib64/qt5/plugins/kstyle_qtcurve5_config.so
#24 0x00007fae7b4dc35a in QtCurveConfig::QtCurveConfig(QWidget*) () from /usr/lib64/qt5/plugins/kstyle_qtcurve5_config.so
#25 0x00007fae7b4dc3f1 in allocate_kstyle_config () from /usr/lib64/qt5/plugins/kstyle_qtcurve5_config.so
#26 0x00007fae8098d6b1 in KCMStyle::styleSpecificConfig() () from /usr/lib64/qt5/plugins/kcm_style.so
#27 0x00007faea01c39c6 in QMetaObject::activate(QObject*, int, int, void**) () from /usr/lib64/libQt5Core.so.5
#28 0x00007faea175ff12 in QAbstractButton::clicked(bool) () from /usr/lib64/libQt5Widgets.so.5
#29 0x00007faea1760104 in QAbstractButtonPrivate::emitClicked() () from /usr/lib64/libQt5Widgets.so.5
#30 0x00007faea17613f7 in QAbstractButtonPrivate::click() () from /usr/lib64/libQt5Widgets.so.5
#31 0x00007faea17615bc in QAbstractButton::mouseReleaseEvent(QMouseEvent*) () from /usr/lib64/libQt5Widgets.so.5
#32 0x00007faea16c2098 in QWidget::event(QEvent*) () from /usr/lib64/libQt5Widgets.so.5
#33 0x00007faea167d5ac in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib64/libQt5Widgets.so.5
#34 0x00007faea168534d in QApplication::notify(QObject*, QEvent*) () from /usr/lib64/libQt5Widgets.so.5
#35 0x00007faea019d99a in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib64/libQt5Core.so.5
#36 0x00007faea1683ddd in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&, bool) () from /usr/lib64/libQt5Widgets.so.5
#37 0x00007faea16dbd5e in QWidgetWindow::handleMouseEvent(QMouseEvent*) () from /usr/lib64/libQt5Widgets.so.5
#38 0x00007faea16de60b in QWidgetWindow::event(QEvent*) () from /usr/lib64/libQt5Widgets.so.5
#39 0x00007faea167d5ac in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib64/libQt5Widgets.so.5
#40 0x00007faea1684819 in QApplication::notify(QObject*, QEvent*) () from /usr/lib64/libQt5Widgets.so.5
#41 0x00007faea019d99a in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib64/libQt5Core.so.5
#42 0x00007faea118dea3 in QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::MouseEvent*) () from /usr/lib64/libQt5Gui.so.5
#43 0x00007faea118f8e5 in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) () from /usr/lib64/libQt5Gui.so.5
#44 0x00007faea116fa9b in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQt5Gui.so.5
#45 0x00007fae92d242d0 in userEventSourceDispatch(_GSource*, int (*)(void*), void*) () from /usr/lib64/libQt5XcbQpa.so.5
#46 0x00007fae9816d177 in g_main_context_dispatch () from /usr/lib64/libglib-2.0.so.0
#47 0x00007fae9816d3a8 in g_main_context_iterate.isra () from /usr/lib64/libglib-2.0.so.0
#48 0x00007fae9816d44c in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#49 0x00007faea01e91ef in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQt5Core.so.5
#50 0x00007faea019ca2a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib64/libQt5Core.so.5
#51 0x00007faea01a42a4 in QCoreApplication::exec() () from /usr/lib64/libQt5Core.so.5
#52 0x000000000040b621 in main ()

Reported using DrKonqi