SUMMARY
I don't have much to add here, except that Wi-Fi was disabled somehow when I logged in, which makes me think it could be related to https://bugs.kde.org/show_bug.cgi?id=397624
But the stack trace seems to mention touchpad.

SOFTWARE/OS VERSIONS
Operating System: openSUSE Leap 15.1
KDE Plasma Version: 5.17.90 (X11 session)
KDE Frameworks Version: 5.66.0
Qt Version: 5.14.1
Kernel Version: 5.5.0-1.g3f183bf-default
OS Type: 64-bit 

ADDITIONAL INFORMATION
Here is a stack trace that drkonqi thinks is useful:
Application: kded5 (kded5), signal: Segmentation fault
Using host libthread_db library "/lib64/libthread_db.so.1".
29	  return SYSCALL_CANCEL (poll, fds, nfds, timeout);
[Current thread is 1 (Thread 0x7f0bf86ecd80 (LWP 16226))]

Thread 7 (Thread 0x7f0ba62c7700 (LWP 16498)):
#0  0x00007f0bf208afb9 in g_mutex_lock () at /usr/lib64/libglib-2.0.so.0
#1  0x00007f0bf2044d56 in g_main_context_dispatch () at /usr/lib64/libglib-2.0.so.0
#2  0x00007f0bf2045230 in  () at /usr/lib64/libglib-2.0.so.0
#3  0x00007f0bf20452bc in g_main_context_iteration () at /usr/lib64/libglib-2.0.so.0
#4  0x00007f0bf610a7eb in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7f0ba0000b10, flags=...) at kernel/qeventdispatcher_glib.cpp:425
#5  0x00007f0bf60a9d4a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7f0ba62c6cb0, flags=..., flags@entry=...) at kernel/qeventloop.cpp:225
#6  0x00007f0bf5eba657 in QThread::exec() (this=<optimized out>) at thread/qthread.cpp:536
#7  0x00007f0bf5ebbb2c in QThreadPrivate::start(void*) (arg=0x55b9a9bb5b60) at thread/qthread_unix.cpp:342
#8  0x00007f0bf54a2569 in start_thread (arg=0x7f0ba62c7700) at pthread_create.c:465
#9  0x00007f0bf57b19ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 6 (Thread 0x7f0bd1c3b700 (LWP 16315)):
#0  0x00007f0bf57a2c98 in __GI___libc_read (fd=21, buf=0x7f0bd1c3abd0, nbytes=16) at ../sysdeps/unix/sysv/linux/read.c:26
#1  0x00007f0bf2089c80 in  () at /usr/lib64/libglib-2.0.so.0
#2  0x00007f0bf2044cb8 in g_main_context_check () at /usr/lib64/libglib-2.0.so.0
#3  0x00007f0bf2045150 in  () at /usr/lib64/libglib-2.0.so.0
#4  0x00007f0bf2045542 in g_main_loop_run () at /usr/lib64/libglib-2.0.so.0
#5  0x00007f0bd71a5e36 in  () at /usr/lib64/libgio-2.0.so.0
#6  0x00007f0bf206cac6 in  () at /usr/lib64/libglib-2.0.so.0
#7  0x00007f0bf54a2569 in start_thread (arg=0x7f0bd1c3b700) at pthread_create.c:465
#8  0x00007f0bf57b19ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 5 (Thread 0x7f0bd243c700 (LWP 16314)):
#0  0x00007f0bf57a719b in __GI___poll (fds=0x7f0bcc005f50, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f0bf20451a9 in  () at /usr/lib64/libglib-2.0.so.0
#2  0x00007f0bf20452bc in g_main_context_iteration () at /usr/lib64/libglib-2.0.so.0
#3  0x00007f0bf2045301 in  () at /usr/lib64/libglib-2.0.so.0
#4  0x00007f0bf206cac6 in  () at /usr/lib64/libglib-2.0.so.0
#5  0x00007f0bf54a2569 in start_thread (arg=0x7f0bd243c700) at pthread_create.c:465
#6  0x00007f0bf57b19ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 4 (Thread 0x7f0bd2c3d700 (LWP 16313)):
#0  0x00007f0bf57a2c98 in __GI___libc_read (fd=18, buf=0x7f0bd2c3cbe0, nbytes=16) at ../sysdeps/unix/sysv/linux/read.c:26
#1  0x00007f0bf2089c80 in  () at /usr/lib64/libglib-2.0.so.0
#2  0x00007f0bf2044cb8 in g_main_context_check () at /usr/lib64/libglib-2.0.so.0
#3  0x00007f0bf2045150 in  () at /usr/lib64/libglib-2.0.so.0
#4  0x00007f0bf20452bc in g_main_context_iteration () at /usr/lib64/libglib-2.0.so.0
#5  0x00007f0bd2c458bd in  () at /usr/lib64/gio/modules/libdconfsettings.so
#6  0x00007f0bf206cac6 in  () at /usr/lib64/libglib-2.0.so.0
#7  0x00007f0bf54a2569 in start_thread (arg=0x7f0bd2c3d700) at pthread_create.c:465
#8  0x00007f0bf57b19ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x7f0bde33c700 (LWP 16241)):
#0  0x00007f0bf57a7171 in __GI___poll (fds=0x7f0bd8025630, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:27
#1  0x00007f0bf20451a9 in  () at /usr/lib64/libglib-2.0.so.0
#2  0x00007f0bf20452bc in g_main_context_iteration () at /usr/lib64/libglib-2.0.so.0
#3  0x00007f0bf610a7eb in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x7f0bd8000b10, flags=...) at kernel/qeventdispatcher_glib.cpp:425
#4  0x00007f0bf60a9d4a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7f0bde33bc80, flags=..., flags@entry=...) at kernel/qeventloop.cpp:225
#5  0x00007f0bf5eba657 in QThread::exec() (this=<optimized out>) at thread/qthread.cpp:536
#6  0x00007f0bf6827115 in  () at /usr/lib64/libQt5DBus.so.5
#7  0x00007f0bf5ebbb2c in QThreadPrivate::start(void*) (arg=0x7f0bf6a9eda0) at thread/qthread_unix.cpp:342
#8  0x00007f0bf54a2569 in start_thread (arg=0x7f0bde33c700) at pthread_create.c:465
#9  0x00007f0bf57b19ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7f0beaeec700 (LWP 16227)):
#0  0x00007f0bf57a719b in __GI___poll (fds=0x7f0beaeebbb8, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007f0bf1ddb307 in  () at /usr/lib64/libxcb.so.1
#2  0x00007f0bf1ddcf3a in xcb_wait_for_event () at /usr/lib64/libxcb.so.1
#3  0x00007f0bedace200 in QXcbEventQueue::run() (this=0x55b9a960f4e0) at qxcbeventqueue.cpp:228
#4  0x00007f0bf5ebbb2c in QThreadPrivate::start(void*) (arg=0x55b9a960f4e0) at thread/qthread_unix.cpp:342
#5  0x00007f0bf54a2569 in start_thread (arg=0x7f0beaeec700) at pthread_create.c:465
#6  0x00007f0bf57b19ef in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7f0bf86ecd80 (LWP 16226)):
[KCrash Handler]
#6  0x00007f0bf45797b5 in XPending () at /usr/lib64/libX11.so.6
#7  0x00007f0ba415b2f8 in XlibNotifications::processEvents() (this=0x55b9a9b19e50) at /usr/src/debug/plasma5-desktop-5.17.90-lp151.395.1.x86_64/kcms/touchpad/src/backends/x11/xlibnotifications.cpp:79
#8  0x00007f0ba415b34e in XlibNotifications::qt_static_metacall(QObject*, QMetaObject::Call, int, void**) (_o=<optimized out>, _id=<optimized out>, _a=<optimized out>, _c=<optimized out>) at /usr/src/debug/plasma5-desktop-5.17.90-lp151.395.1.x86_64/build/kcms/touchpad/src/kded_touchpad_autogen/include/moc_xlibnotifications.cpp:91
#9  0x00007f0bf60e64d9 in doActivate<false>(QObject*, int, void**) (sender=0x55b9a9727580, signal_index=3, argv=0x7ffc6b31b120) at kernel/qobject.cpp:3882
#10 0x00007f0bf60e0fb2 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) (sender=sender@entry=0x55b9a9727580, m=m@entry=0x7f0bf6567b80 <QSocketNotifier::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x7ffc6b31b120) at kernel/qobject.cpp:3930
#11 0x00007f0bf60e9cd8 in QSocketNotifier::activated(int, QSocketNotifier::QPrivateSignal) (this=this@entry=0x55b9a9727580, _t1=<optimized out>, _t2=...) at .moc/moc_qsocketnotifier.cpp:141
#12 0x00007f0bf60ea092 in QSocketNotifier::event(QEvent*) (this=0x55b9a9727580, e=0x7ffc6b31b3f0) at kernel/qsocketnotifier.cpp:266
#13 0x00007f0bf7e0db5c in QApplicationPrivate::notify_helper(QObject*, QEvent*) (this=this@entry=0x55b9a95eb8d0, receiver=receiver@entry=0x55b9a9727580, e=e@entry=0x7ffc6b31b3f0) at kernel/qapplication.cpp:3684
#14 0x00007f0bf7e14d60 in QApplication::notify(QObject*, QEvent*) (this=0x7ffc6b31b6c0, receiver=0x55b9a9727580, e=0x7ffc6b31b3f0) at kernel/qapplication.cpp:3430
#15 0x00007f0bf60ab4c8 in QCoreApplication::notifyInternal2(QObject*, QEvent*) (receiver=0x55b9a9727580, event=0x7ffc6b31b3f0) at kernel/qcoreapplication.cpp:1092
#16 0x00007f0bf60ab69e in QCoreApplication::sendEvent(QObject*, QEvent*) (receiver=<optimized out>, event=event@entry=0x7ffc6b31b3f0) at kernel/qcoreapplication.cpp:1487
#17 0x00007f0bf610b398 in socketNotifierSourceDispatch(GSource*, GSourceFunc, gpointer) (source=0x55b9a96724c0) at kernel/qeventdispatcher_glib.cpp:107
#18 0x00007f0bf2044e87 in g_main_context_dispatch () at /usr/lib64/libglib-2.0.so.0
#19 0x00007f0bf2045230 in  () at /usr/lib64/libglib-2.0.so.0
#20 0x00007f0bf20452bc in g_main_context_iteration () at /usr/lib64/libglib-2.0.so.0
#21 0x00007f0bf610a7cc in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) (this=0x55b9a9682470, flags=...) at kernel/qeventdispatcher_glib.cpp:423
#22 0x00007f0bf60a9d4a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) (this=this@entry=0x7ffc6b31b610, flags=..., flags@entry=...) at kernel/qeventloop.cpp:225
#23 0x00007f0bf60b34c0 in QCoreApplication::exec() () at kernel/qcoreapplication.cpp:1400
#24 0x000055b9a89838e4 in main(int, char**) (argc=<optimized out>, argv=<optimized out>) at /usr/src/debug/kded-5.66.0-lp151.190.2.x86_64/src/kded.cpp:804
[Inferior 1 (process 16226) detached]