KDE plasma System Settings crash

I get a segmentation fault in System Settings while switching from certain settings to any other one. I discovered this when I tried to use the magnifier in Desktop Effects. I can reach General Behavior in Workspace Behavior, but when I try to select Desktop Effects after that, it crashes.

Operating System: Manjaro Linux 
KDE Plasma Version: 5.18.5
KDE Frameworks Version: 5.70.0
Qt Version: 5.14.2
Kernel Version: 5.7.0-1-MANJARO
OS Type: 64-bit
Processors: 4 × Intel® Core™ i5-7200U CPU @ 2.50GHz
Memory: 7,7 GiB of RAM

Thread 1 (Thread 0x7f043adaf300 (LWP 3795)):
[KCrash Handler]
#4  0x0000000000000000 in ?? ()
#5  0x00007f043ed28fa7 in ?? () from /usr/lib/libQt5Quick.so.5
#6  0x00007f043ed29019 in ?? () from /usr/lib/libQt5Quick.so.5
#7  0x00007f043eeefa93 in ?? () from /usr/lib/libQt5Quick.so.5
#8  0x00007f043a99147a in ?? () from /usr/lib/libQt5XcbQpa.so.5
#9  0x00007f043a994933 in ?? () from /usr/lib/libQt5XcbQpa.so.5
#10 0x00007f043a995954 in ?? () from /usr/lib/libQt5XcbQpa.so.5
#11 0x00007f043ed36d3d in QQuickItemPrivate::setEffectiveVisibleRecur(bool) () from /usr/lib/libQt5Quick.so.5
#12 0x00007f043ed36e25 in QQuickItemPrivate::setVisible(bool) () from /usr/lib/libQt5Quick.so.5
#13 0x00007f0425113c31 in ?? () from /usr/lib/qt/qml/org/kde/kirigami.2/libkirigamiplugin.so
#14 0x00007f0425115898 in ?? () from /usr/lib/qt/qml/org/kde/kirigami.2/libkirigamiplugin.so
#15 0x00007f043ed36715 in QQuickItemPrivate::itemChange(QQuickItem::ItemChange, QQuickItem::ItemChangeData const&) () from /usr/lib/libQt5Quick.so.5
#16 0x00007f043ed3cd88 in QQuickItemPrivate::removeChild(QQuickItem*) () from /usr/lib/libQt5Quick.so.5
#17 0x00007f043ed3d3e2 in QQuickItem::setParentItem(QQuickItem*) () from /usr/lib/libQt5Quick.so.5
#18 0x00007f043ed3f0c9 in QQuickItem::~QQuickItem() () from /usr/lib/libQt5Quick.so.5
#19 0x00007f0424e4fcd7 in ?? () from /usr/lib/qt/qml/QtQuick/Templates.2/libqtquicktemplates2plugin.so
#20 0x00007f043f06393d in KDeclarative::QmlObject::~QmlObject() () from /usr/lib/libKF5Declarative.so.5
#21 0x00007f043f06445a in KDeclarative::QmlObjectSharedEngine::~QmlObjectSharedEngine() () from /usr/lib/libKF5Declarative.so.5
#22 0x00007f0440e80762 in KQuickAddons::ConfigModule::~ConfigModule() () from /usr/lib/libKF5QuickAddons.so.5
#23 0x00007f041d9a3519 in ?? () from /usr/lib/qt/plugins/kcms/kcm_lookandfeel.so
#24 0x00007f0440fa2843 in ?? () from /usr/lib/libKF5KCMUtils.so.5
#25 0x00007f0440fa2879 in ?? () from /usr/lib/libKF5KCMUtils.so.5
#26 0x00007f0440fa8744 in KCModuleProxy::deleteClient() () from /usr/lib/libKF5KCMUtils.so.5
#27 0x00007f0440fa883e in KCModuleProxy::~KCModuleProxy() () from /usr/lib/libKF5KCMUtils.so.5
#28 0x00007f0440fa89ea in KCModuleProxy::~KCModuleProxy() () from /usr/lib/libKF5KCMUtils.so.5
#29 0x00007f043f8f45ae in QObjectPrivate::deleteChildren() () from /usr/lib/libQt5Core.so.5
#30 0x00007f0440441ade in QWidget::~QWidget() () from /usr/lib/libQt5Widgets.so.5
#31 0x00007f0440441cfa in QWidget::~QWidget() () from /usr/lib/libQt5Widgets.so.5
#32 0x00007f043f8f45ae in QObjectPrivate::deleteChildren() () from /usr/lib/libQt5Core.so.5
#33 0x00007f0440441ade in QWidget::~QWidget() () from /usr/lib/libQt5Widgets.so.5
#34 0x00007f04405a7c8a in QScrollArea::~QScrollArea() () from /usr/lib/libQt5Widgets.so.5
#35 0x00007f0440cd9b46 in KPageWidgetItem::~KPageWidgetItem() () from /usr/lib/libKF5WidgetsAddons.so.5
#36 0x00007f0440cd9c1a in KPageWidgetItem::~KPageWidgetItem() () from /usr/lib/libKF5WidgetsAddons.so.5
#37 0x00007f0440cda6eb in ?? () from /usr/lib/libKF5WidgetsAddons.so.5
#38 0x00007f0440cdb2df in KPageWidgetModel::removePage(KPageWidgetItem*) () from /usr/lib/libKF5WidgetsAddons.so.5
#39 0x00007f0440fed04e in ModuleView::closeModules() () from /usr/lib/libsystemsettingsview.so.3
#40 0x00007f0426ba1d42 in ?? () from /usr/lib/qt/plugins/systemsettings_sidebar_mode.so
#41 0x00007f0426b9f5ad in ?? () from /usr/lib/qt/plugins/systemsettings_sidebar_mode.so
#42 0x00007f0426b9fc03 in ?? () from /usr/lib/qt/plugins/systemsettings_sidebar_mode.so
#43 0x00007f043e92857e in ?? () from /usr/lib/libQt5Qml.so.5
#44 0x00007f043e8037f6 in ?? () from /usr/lib/libQt5Qml.so.5
#45 0x00007f043e805acc in ?? () from /usr/lib/libQt5Qml.so.5
#46 0x00007f043e8068de in QV4::QObjectMethod::callInternal(QV4::Value const*, QV4::Value const*, int) const () from /usr/lib/libQt5Qml.so.5
#47 0x00007f043e825226 in ?? () from /usr/lib/libQt5Qml.so.5
#48 0x00007f043e82719f in ?? () from /usr/lib/libQt5Qml.so.5
#49 0x00007f043e7b6b3e in QV4::Function::call(QV4::Value const*, QV4::Value const*, int, QV4::ExecutionContext const*) () from /usr/lib/libQt5Qml.so.5
#50 0x00007f043e946b78 in QQmlJavaScriptExpression::evaluate(QV4::CallData*, bool*) () from /usr/lib/libQt5Qml.so.5
#51 0x00007f043e8ecfaf in QQmlBoundSignalExpression::evaluate(void**) () from /usr/lib/libQt5Qml.so.5
#52 0x00007f043e8ee069 in ?? () from /usr/lib/libQt5Qml.so.5
#53 0x00007f043e927fdd in QQmlNotifier::emitNotify(QQmlNotifierEndpoint*, void**) () from /usr/lib/libQt5Qml.so.5
#54 0x00007f043e8cf80e in QQmlData::signalEmitted(QAbstractDeclarativeData*, QObject*, int, void**) () from /usr/lib/libQt5Qml.so.5
#55 0x00007f043f8ff855 in ?? () from /usr/lib/libQt5Core.so.5
#56 0x00007f0439b6f782 in QQuickAbstractButtonPrivate::handleRelease(QPointF const&) () from /usr/lib/libQt5QuickTemplates2.so.5
#57 0x00007f0439b8dc35 in QQuickControl::mouseReleaseEvent(QMouseEvent*) () from /usr/lib/libQt5QuickTemplates2.so.5
#58 0x00007f043ed3c498 in QQuickItem::event(QEvent*) () from /usr/lib/libQt5Quick.so.5
#59 0x00007f0440402352 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#60 0x00007f044040b829 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#61 0x00007f043f8ca4f2 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib/libQt5Core.so.5
#62 0x00007f043ed58079 in QQuickWindowPrivate::deliverMouseEvent(QQuickPointerMouseEvent*) () from /usr/lib/libQt5Quick.so.5
#63 0x00007f043ed59808 in QQuickWindowPrivate::deliverPointerEvent(QQuickPointerEvent*) () from /usr/lib/libQt5Quick.so.5
#64 0x00007f043ed5a5f8 in QQuickWindowPrivate::handleMouseEvent(QMouseEvent*) () from /usr/lib/libQt5Quick.so.5
#65 0x00007f043fd389cd in QWindow::event(QEvent*) () from /usr/lib/libQt5Gui.so.5
#66 0x00007f043ed5c093 in QQuickWindow::event(QEvent*) () from /usr/lib/libQt5Quick.so.5
#67 0x00007f0440402352 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#68 0x00007f044040b829 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#69 0x00007f043f8ca4f2 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib/libQt5Core.so.5
#70 0x00007f043f0790da in QQuickWidget::mouseReleaseEvent(QMouseEvent*) () from /usr/lib/libQt5QuickWidgets.so.5
#71 0x00007f04404462ee in QWidget::event(QEvent*) () from /usr/lib/libQt5Widgets.so.5
#72 0x00007f043f079294 in QQuickWidget::event(QEvent*) () from /usr/lib/libQt5QuickWidgets.so.5
#73 0x00007f0440402352 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#74 0x00007f044040ba78 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#75 0x00007f043f8ca4f2 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib/libQt5Core.so.5
#76 0x00007f044040aaeb in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&, bool, bool) () from /usr/lib/libQt5Widgets.so.5
#77 0x00007f0440461b21 in ?? () from /usr/lib/libQt5Widgets.so.5
#78 0x00007f0440464aa4 in ?? () from /usr/lib/libQt5Widgets.so.5
#79 0x00007f0440402352 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#80 0x00007f044040b829 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQt5Widgets.so.5
#81 0x00007f043f8ca4f2 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib/libQt5Core.so.5
#82 0x00007f043fd2d2a4 in QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::MouseEvent*) () from /usr/lib/libQt5Gui.so.5
#83 0x00007f043fd2e9b6 in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) () from /usr/lib/libQt5Gui.so.5
#84 0x00007f043fd06c5c in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Gui.so.5
#85 0x00007f043a918e2c in ?? () from /usr/lib/libQt5XcbQpa.so.5
#86 0x00007f043d51d6be in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#87 0x00007f043d51f531 in ?? () from /usr/lib/libglib-2.0.so.0
#88 0x00007f043d51f571 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#89 0x00007f043f922890 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#90 0x00007f043f8c905c in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#91 0x00007f043f8d1066 in QCoreApplication::exec() () from /usr/lib/libQt5Core.so.5
#92 0x000055eb7a5df46c in ?? ()
#93 0x00007f043f29d023 in __libc_start_main () from /usr/lib/libc.so.6
#94 0x000055eb7a5df4fe in _start ()
[Inferior 1 (process 3795) detached]

Can I fix this by reverting a library to a previous version? If that's not possible. which library do I need to debug?

If you have a timeshift backup you can go back - but reverting a single package is usually a bad idea - it may create other issues - making it even harder to trouble shoot.

Your best bet is bugs.kde.org - see if a report exist on a similar issue - or create a new issue.

I just created a new user. After logging in, System Settings doesn't crash anymore.
It seems the KDE settings are the problem. How do I reset them?

You can try cleaning the cache first.

Didn't help ... there are several .config/plasma* files and a folder plasma-workspace. Which of these should I delete?

Move (instead of delete) them all and add them back one at a time until you find your culprit.

So ... I figured it out. The word completion feature of the Onboard virtual keyboard uses GNOME accessibility which causes KDE System Settings to crash. As soon as I quit Onboard, no more crash.

Mystery solved. Now ... who do I blame? Manjaro, Arch, KDE, GNOME, Onboard ... or myself? :sweat_smile:

I can confirm this bug. I'm running KDE Plasma 5.19.2 from testing on a Microsoft Surface Pro 4 tablet PC. I heavily rely on Onboard. I noticed that systemsettings5 was sluggish and crashing every time I hit the "All Settings" back arrow. After some time, I narrowed the problem to Onboard. After adjusting some settings in Onboard, I narrowed the problem down further to the word completion and auto show options. If these options are enabled, systemsettings5 crashes and dumps a core file when I hit "All Settings." THIS IS A MANJARO ISSUE! I triple boot Manjaro KDE, KDE Neon, and Windows 10 on the same machine. I can confirm that this does not happen in KDE Neon.

System: Host: kelvin-sp4 Kernel: 4.19.129-1-surface-lts x86_64 bits: 64 compiler: gcc
v: 10.1.0 Desktop: KDE Plasma 5.19.2 Distro: Manjaro Linux
Machine: Type: Laptop System: Microsoft product: Surface Pro 4
v: 124000000000000000000000D:0B:08F:1C:03P:38 serial:
Mobo: Microsoft model: Surface Pro 4 serial: UEFI: Microsoft
v: 109.3192.768 date: 03.24.2020
Battery: ID-1: BAT1 charge: 17.0 Wh condition: 35.7/38.2 Wh (94%) model: SMP X910527
status: Discharging
CPU: Topology: Dual Core model: Intel Core i5-6300U bits: 64 type: MT MCP arch: Skylake
rev: 3 L2 cache: 3072 KiB
flags: avx avx2 lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx bogomips: 19968
Speed: 814 MHz min/max: 400/3000 MHz Core speeds (MHz): 1: 814 2: 2243 3: 1763
4: 1577
Graphics: Device-1: Intel Skylake GT2 [HD Graphics 520] vendor: Microsoft driver: i915
v: kernel bus ID: 00:02.0
Display: x11 server: X.Org 1.20.8 driver: intel resolution: 2736x1824~60Hz
OpenGL: renderer: Mesa Intel HD Graphics 520 (SKL GT2) v: 4.6 Mesa 20.1.2
direct render: Yes
Audio: Device-1: Intel Xeon E3-1200 v5/E3-1500 v5/6th Gen Core Processor Imaging Unit
driver: N/A bus ID: 00:05.0
Device-2: Intel driver: N/A bus ID: 00:14.3
Device-3: Intel Sunrise Point-LP HD Audio driver: snd_hda_intel v: kernel
bus ID: 00:1f.3
Sound Server: ALSA v: k4.19.129-1-surface-lts
Network: Device-1: Marvell 88W8897 [AVASTAR] 802.11ac Wireless driver: mwifiex_pcie v: 1.0
port: 3000 bus ID: 02:00.0
IF: wlp2s0 state: up mac:
Device-2: Marvell Bluetooth and Wireless LAN Composite Device type: USB
driver: btusb bus ID: 1-5:2
Drives: Local Storage: total: 476.94 GiB used: 205.57 GiB (43.1%)
ID-1: /dev/nvme0n1 vendor: Samsung model: MZFLV512HCJH-000MV size: 476.94 GiB
Partition: ID-1: / size: 30.63 GiB used: 21.56 GiB (70.4%) fs: ext4 dev: /dev/nvme0n1p5
ID-2: swap-1 size: 29.80 GiB used: 29.2 MiB (0.1%) fs: swap dev: /dev/nvme0n1p6
Sensors: System Temperatures: cpu: 41.0 C mobo: 0.0 C
Fan Speeds (RPM): N/A
Info: Processes: 210 Uptime: 13h 25m Memory: 15.59 GiB used: 1.87 GiB (12.0%)
Init: systemd Compilers: gcc: 10.1.0 Shell: bash v: 5.0.17 inxi: 3.0.37

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