Every time I try to log out or shut down, ksmserver-logout-greeter crashes.

Application: ksmserver-logout-greeter (ksmserver-logout-greeter), signal: Segmentation fault
Using host libthread_db library "/usr/lib/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fae26c50d40 (LWP 10917))]

Thread 2 (Thread 0x7fae11690700 (LWP 10919)):
#0  0x00007fae22f8a800 in ?? () from /usr/lib/libQt5Core.so.5
#1  0x00007fae1b243e8d in g_main_context_prepare () from /usr/lib/libglib-2.0.so.0
#2  0x00007fae1b2448db in ?? () from /usr/lib/libglib-2.0.so.0
#3  0x00007fae1b244acc in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#4  0x00007fae22f8b01b in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#5  0x00007fae22f3484a in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQt5Core.so.5
#6  0x00007fae22d569f3 in QThread::exec() () from /usr/lib/libQt5Core.so.5
#7  0x00007fae23adb125 in ?? () from /usr/lib/libQt5DBus.so.5
#8  0x00007fae22d5b658 in ?? () from /usr/lib/libQt5Core.so.5
#9  0x00007fae1d18c2e7 in start_thread () from /usr/lib/libpthread.so.0
#10 0x00007fae2266e54f in clone () from /usr/lib/libc.so.6

Thread 1 (Thread 0x7fae26c50d40 (LWP 10917)):
[KCrash Handler]
#6  0x00007fae1da15d49 in wl_map_insert_at () from /usr/lib/libwayland-client.so.0
#7  0x00007fae1da11f1e in wl_proxy_destroy () from /usr/lib/libwayland-client.so.0
#8  0x00007fae2608b285 in KWayland::Client::Registry::release() () from /usr/lib/libKF5WaylandClient.so.5
#9  0x00007fae2608b2ae in KWayland::Client::Registry::~Registry() () from /usr/lib/libKF5WaylandClient.so.5
#10 0x00007fae2608b389 in KWayland::Client::Registry::~Registry() () from /usr/lib/libKF5WaylandClient.so.5
#11 0x00007fae22f603c1 in QObjectPrivate::deleteChildren() () from /usr/lib/libQt5Core.so.5
#12 0x00007fae22f69d1f in QObject::~QObject() () from /usr/lib/libQt5Core.so.5
#13 0x00007fae032d8393 in ?? () from /usr/lib/qt/plugins/kf5/org.kde.kwindowsystem.platforms/KF5WindowSystemKWaylandPlugin.so
#14 0x00007fae225b86c0 in __run_exit_handlers () from /usr/lib/libc.so.6
#15 0x00007fae225b871a in exit () from /usr/lib/libc.so.6
#16 0x00007fae225a2518 in __libc_start_main () from /usr/lib/libc.so.6
#17 0x0000000000405c4a in _start ()