I updated from Ubuntu 18.04.5 LTS to 20.04.1 LTS with do-release-upgrade. After the update, the system settings application crashes every time I try to open system settings.


STEPS TO REPRODUCE
1. Select KMenu>Settings>System Settings or type "systemsettings5" in a terminal.

OBSERVED RESULT
When I try "systemsettings5" from a terminal, the following happens:

i@numenor ~ $ systemsettings5 
QQmlEngine::setContextForObject(): Object already has a QQmlContext
KCrash: crashing... crashRecursionCounter = 2
KCrash: Application Name = systemsettings5 path = /usr/bin pid = 10239
KCrash: Arguments: /usr/bin/systemsettings5 
KCrash: Attempting to start /usr/lib/x86_64-linux-gnu/libexec/drkonqi from kdeinit
sock_file=/run/user/32969/kdeinit5__0

[1]+  Stopped                 systemsettings5
i@numenor ~ $ QSocketNotifier: Invalid socket 8 and type 'Read', disabling...
QSocketNotifier: Invalid socket 9 and type 'Read', disabling...

Note that I did not hit Ctrl+Z to send systemsettings5 to the background, that happened automatically. After it goes to the background, I get a couple more lines of output,

QSocketNotifier: Invalid socket 8 and type 'Read', disabling...
QSocketNotifier: Invalid socket 9 and type 'Read', disabling...

and then nothing more. At this point, I can bring it back to foreground by 'fg', but that doesn't change anything, it has crashed/segfaulted already. I gathered the following backtrace from Dr Konqui:

Application: System Settings (systemsettings5), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f9ec59a0800 (LWP 10239))]

Thread 9 (Thread 0x7f9eab5ef700 (LWP 10248)):
#0  __GI___libc_read (nbytes=16, buf=0x7f9eab5eeb70, fd=18) at ../sysdeps/unix/sysv/linux/read.c:26
#1  __GI___libc_read (fd=18, buf=0x7f9eab5eeb70, nbytes=16) at ../sysdeps/unix/sysv/linux/read.c:24
#2  0x00007f9ec7dbc89f in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f9ec7d73cfe in g_main_context_check () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f9ec7d74152 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#5  0x00007f9ec7d742e3 in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#6  0x00007f9eca03a583 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f9ec9fe14db in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007f9ec9e19785 in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007f9ec90cc1a9 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#10 0x00007f9ec9e1a9d2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#11 0x00007f9ec8658609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#12 0x00007f9ec9aab293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 8 (Thread 0x7f9eb1979700 (LWP 10247)):
#0  0x00007f9ec7dc133d in g_mutex_lock () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#1  0x00007f9ec7d7373a in g_main_context_prepare () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f9ec7d740db in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f9ec7d742e3 in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#4  0x00007f9eca03a583 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f9ec9fe14db in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f9ec9e19785 in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f9ec90cc1a9 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Qml.so.5
#8  0x00007f9ec9e1a9d2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#9  0x00007f9ec8658609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#10 0x00007f9ec9aab293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 7 (Thread 0x7f9eaa168700 (LWP 10245)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x5603831ec588) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x5603831ec538, cond=0x5603831ec560) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x5603831ec560, mutex=0x5603831ec538) at pthread_cond_wait.c:638
#3  0x00007f9ebcf4562b in ?? () from /usr/lib/x86_64-linux-gnu/dri/iris_dri.so
#4  0x00007f9ebcf4523b in ?? () from /usr/lib/x86_64-linux-gnu/dri/iris_dri.so
#5  0x00007f9ec8658609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f9ec9aab293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 6 (Thread 0x7f9eb2969700 (LWP 10244)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x5603831ec588) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x5603831ec538, cond=0x5603831ec560) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x5603831ec560, mutex=0x5603831ec538) at pthread_cond_wait.c:638
#3  0x00007f9ebcf4562b in ?? () from /usr/lib/x86_64-linux-gnu/dri/iris_dri.so
#4  0x00007f9ebcf4523b in ?? () from /usr/lib/x86_64-linux-gnu/dri/iris_dri.so
#5  0x00007f9ec8658609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f9ec9aab293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 5 (Thread 0x7f9eb316a700 (LWP 10243)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x5603831ec588) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x5603831ec538, cond=0x5603831ec560) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x5603831ec560, mutex=0x5603831ec538) at pthread_cond_wait.c:638
#3  0x00007f9ebcf4562b in ?? () from /usr/lib/x86_64-linux-gnu/dri/iris_dri.so
#4  0x00007f9ebcf4523b in ?? () from /usr/lib/x86_64-linux-gnu/dri/iris_dri.so
#5  0x00007f9ec8658609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f9ec9aab293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 4 (Thread 0x7f9eb396b700 (LWP 10242)):
#0  futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x5603831ec588) at ../sysdeps/nptl/futex-internal.h:183
#1  __pthread_cond_wait_common (abstime=0x0, clockid=0, mutex=0x5603831ec538, cond=0x5603831ec560) at pthread_cond_wait.c:508
#2  __pthread_cond_wait (cond=0x5603831ec560, mutex=0x5603831ec538) at pthread_cond_wait.c:638
#3  0x00007f9ebcf4562b in ?? () from /usr/lib/x86_64-linux-gnu/dri/iris_dri.so
#4  0x00007f9ebcf4523b in ?? () from /usr/lib/x86_64-linux-gnu/dri/iris_dri.so
#5  0x00007f9ec8658609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f9ec9aab293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x7f9ebfb68700 (LWP 10241)):
#0  0x00007f9ec7d736c8 in g_main_context_prepare () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#1  0x00007f9ec7d740db in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f9ec7d742e3 in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f9eca03a583 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007f9ec9fe14db in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f9ec9e19785 in QThread::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007f9eca2bcefa in ?? () from /usr/lib/x86_64-linux-gnu/libQt5DBus.so.5
#7  0x00007f9ec9e1a9d2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007f9ec8658609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#9  0x00007f9ec9aab293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7f9ec4aeb700 (LWP 10240)):
#0  0x00007f9ec9a9eaff in __GI___poll (fds=0x7f9ec4aeaca8, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f9ec8615c1a in ?? () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007f9ec861790a in xcb_wait_for_event () from /usr/lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007f9ec52ef298 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#4  0x00007f9ec9e1a9d2 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007f9ec8658609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#6  0x00007f9ec9aab293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7f9ec59a0800 (LWP 10239)):
[KCrash Handler]
#6  0x00007f9ebd5eac14 in ?? () from /usr/lib/x86_64-linux-gnu/dri/iris_dri.so
#7  0x00007f9ebd7afa84 in ?? () from /usr/lib/x86_64-linux-gnu/dri/iris_dri.so
#8  0x00007f9ebd5c686d in ?? () from /usr/lib/x86_64-linux-gnu/dri/iris_dri.so
#9  0x00007f9ebd5c74a5 in ?? () from /usr/lib/x86_64-linux-gnu/dri/iris_dri.so
#10 0x00007f9ebcc058d4 in ?? () from /usr/lib/x86_64-linux-gnu/dri/iris_dri.so
#11 0x00007f9eca7758d8 in QPlatformBackingStore::composeAndFlush(QWindow*, QRegion const&, QPoint const&, QPlatformTextureList*, bool) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#12 0x00007f9ec52e3008 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#13 0x00007f9ecaaa5e84 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#14 0x00007f9ecaaa7898 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#15 0x00007f9ecaaa8c11 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#16 0x00007f9ecaaa93da in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#17 0x00007f9ecaaf78dc in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#18 0x00007f9ecaaf82d0 in ?? () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#19 0x00007f9ecaa96a66 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#20 0x00007f9ecaaa00f0 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#21 0x00007f9ec9fe293a in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#22 0x00007f9eca468de6 in QGuiApplicationPrivate::processExposeEvent(QWindowSystemInterfacePrivate::ExposeEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#23 0x00007f9eca469014 in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#24 0x00007f9eca44335b in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#25 0x00007f9ec52f032e in ?? () from /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#26 0x00007f9ec7d73fbd in g_main_context_dispatch () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#27 0x00007f9ec7d74240 in ?? () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#28 0x00007f9ec7d742e3 in g_main_context_iteration () from /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#29 0x00007f9eca03a565 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#30 0x00007f9ec9fe14db in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#31 0x00007f9ec9fe9246 in QCoreApplication::exec() () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#32 0x0000560380d91856 in ?? ()
#33 0x00007f9ec99b00b3 in __libc_start_main (main=0x560380d91460, argc=1, argv=0x7ffecbda40e8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffecbda40d8) at ../csu/libc-start.c:308
#34 0x0000560380d918de in _start ()
[Inferior 1 (process 10239) detached]

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Kubuntu 20.04
KDE Plasma Version: 5.18.5
KDE Frameworks Version: 5.68.0
Qt Version: 5.12.8

ADDITIONAL INFORMATION