I did login and quickly switched to a VT.

After a while i came back to X11 to found kded4 had crashed.

I've tried reproducing it a few times and could not.

Feel free to close if the backtrace does not give enough info

Application: Dimoni KDE (kded4), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
To enable execution of this file add
	add-auto-load-safe-path /lib/x86_64-linux-gnu/libglib-2.0.so.0.3991.0-gdb.py
line to your configuration file "/home/tsdgeos/.gdbinit".
To completely disable this security protection add
	set auto-load safe-path /
line to your configuration file "/home/tsdgeos/.gdbinit".
For more information about this security protection see the
"Auto-loading safe path" section in the GDB manual.  E.g., run from the shell:
	info "(gdb)Auto-loading safe path"
[Current thread is 1 (Thread 0x7f42f37b37c0 (LWP 2610))]

Thread 5 (Thread 0x7f42d4c8e700 (LWP 2710)):
#0  0x00007f42ee17b60a in g_mutex_get_impl (mutex=0x7f42d00009a0) at /build/buildd/glib2.0-2.39.91/./glib/gthread-posix.c:120
#1  0x00007f42ee17b969 in g_mutex_lock (mutex=mutex@entry=0x7f42d00009a0) at /build/buildd/glib2.0-2.39.91/./glib/gthread-posix.c:209
#2  0x00007f42ee139f99 in g_main_context_iterate (context=context@entry=0x7f42d00009a0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.39.91/./glib/gmain.c:3738
#3  0x00007f42ee13a0ec in g_main_context_iteration (context=0x7f42d00009a0, may_block=1) at /build/buildd/glib2.0-2.39.91/./glib/gmain.c:3795
#4  0x00007f42f24747be in QEventDispatcherGlib::processEvents (this=0x7f42d00008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:436
#5  0x00007f42f24460af in QEventLoop::processEvents (this=this@entry=0x7f42d4c8de20, flags=...) at kernel/qeventloop.cpp:149
#6  0x00007f42f24463a5 in QEventLoop::exec (this=this@entry=0x7f42d4c8de20, flags=...) at kernel/qeventloop.cpp:204
#7  0x00007f42f2342c5f in QThread::exec (this=<optimized out>) at thread/qthread.cpp:537
#8  0x00007f42f234532f in QThreadPrivate::start (arg=0x1c5be30) at thread/qthread_unix.cpp:349
#9  0x00007f42ee81c182 in start_thread (arg=0x7f42d4c8e700) at pthread_create.c:312
#10 0x00007f42f104812d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 4 (Thread 0x7f42c5b4d700 (LWP 2742)):
#0  g_mutex_get_impl (mutex=0x7f42980009a0) at /build/buildd/glib2.0-2.39.91/./glib/gthread-posix.c:122
#1  0x00007f42ee17b999 in g_mutex_unlock (mutex=mutex@entry=0x7f42980009a0) at /build/buildd/glib2.0-2.39.91/./glib/gthread-posix.c:228
#2  0x00007f42ee1398f9 in g_main_context_query (context=context@entry=0x7f42980009a0, max_priority=2147483647, timeout=timeout@entry=0x7f42c5b4ccac, fds=fds@entry=0x7f4298004d30, n_fds=n_fds@entry=1) at /build/buildd/glib2.0-2.39.91/./glib/gmain.c:3489
#3  0x00007f42ee139f52 in g_main_context_iterate (context=context@entry=0x7f42980009a0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.39.91/./glib/gmain.c:3716
#4  0x00007f42ee13a0ec in g_main_context_iteration (context=0x7f42980009a0, may_block=1) at /build/buildd/glib2.0-2.39.91/./glib/gmain.c:3795
#5  0x00007f42f24747be in QEventDispatcherGlib::processEvents (this=0x7f42980008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:436
#6  0x00007f42f24460af in QEventLoop::processEvents (this=this@entry=0x7f42c5b4cde0, flags=...) at kernel/qeventloop.cpp:149
#7  0x00007f42f24463a5 in QEventLoop::exec (this=this@entry=0x7f42c5b4cde0, flags=...) at kernel/qeventloop.cpp:204
#8  0x00007f42f2342c5f in QThread::exec (this=<optimized out>) at thread/qthread.cpp:537
#9  0x00007f42d7940027 in KCupsConnection::run() () from /usr/lib/libkcupslib.so
#10 0x00007f42f234532f in QThreadPrivate::start (arg=0x1aef6e0) at thread/qthread_unix.cpp:349
#11 0x00007f42ee81c182 in start_thread (arg=0x7f42c5b4d700) at pthread_create.c:312
#12 0x00007f42f104812d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 3 (Thread 0x7f42c534c700 (LWP 2743)):
#0  0x00007f42ee10b860 in pthread_mutex_lock@plt () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#1  0x00007f42ee17b971 in g_mutex_lock (mutex=mutex@entry=0x7f429c0009a0) at /build/buildd/glib2.0-2.39.91/./glib/gthread-posix.c:209
#2  0x00007f42ee1391f8 in g_main_context_release (context=context@entry=0x7f429c0009a0) at /build/buildd/glib2.0-2.39.91/./glib/gmain.c:3158
#3  0x00007f42ee139f91 in g_main_context_iterate (context=context@entry=0x7f429c0009a0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.39.91/./glib/gmain.c:3736
#4  0x00007f42ee13a0ec in g_main_context_iteration (context=0x7f429c0009a0, may_block=1) at /build/buildd/glib2.0-2.39.91/./glib/gmain.c:3795
#5  0x00007f42f24747be in QEventDispatcherGlib::processEvents (this=0x7f429c0008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:436
#6  0x00007f42f24460af in QEventLoop::processEvents (this=this@entry=0x7f42c534be20, flags=...) at kernel/qeventloop.cpp:149
#7  0x00007f42f24463a5 in QEventLoop::exec (this=this@entry=0x7f42c534be20, flags=...) at kernel/qeventloop.cpp:204
#8  0x00007f42f2342c5f in QThread::exec (this=<optimized out>) at thread/qthread.cpp:537
#9  0x00007f42f234532f in QThreadPrivate::start (arg=0x19af8c0) at thread/qthread_unix.cpp:349
#10 0x00007f42ee81c182 in start_thread (arg=0x7f42c534c700) at pthread_create.c:312
#11 0x00007f42f104812d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 2 (Thread 0x7f42c4b4b700 (LWP 2746)):
#0  0x00007f42ee81f7ee in __pthread_mutex_unlock_usercnt (decr=1, mutex=0x7f4290000a60) at pthread_mutex_unlock.c:57
#1  __GI___pthread_mutex_unlock (mutex=0x7f4290000a60) at pthread_mutex_unlock.c:310
#2  0x00007f42ee17b9a1 in g_mutex_unlock (mutex=mutex@entry=0x7f42900009a0) at /build/buildd/glib2.0-2.39.91/./glib/gthread-posix.c:228
#3  0x00007f42ee139bda in g_main_context_dispatch (context=context@entry=0x7f42900009a0) at /build/buildd/glib2.0-2.39.91/./glib/gmain.c:3666
#4  0x00007f42ee13a048 in g_main_context_iterate (context=context@entry=0x7f42900009a0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.39.91/./glib/gmain.c:3734
#5  0x00007f42ee13a0ec in g_main_context_iteration (context=0x7f42900009a0, may_block=1) at /build/buildd/glib2.0-2.39.91/./glib/gmain.c:3795
#6  0x00007f42f24747be in QEventDispatcherGlib::processEvents (this=0x7f42900008c0, flags=...) at kernel/qeventdispatcher_glib.cpp:436
#7  0x00007f42f24460af in QEventLoop::processEvents (this=this@entry=0x7f42c4b4ade0, flags=...) at kernel/qeventloop.cpp:149
#8  0x00007f42f24463a5 in QEventLoop::exec (this=this@entry=0x7f42c4b4ade0, flags=...) at kernel/qeventloop.cpp:204
#9  0x00007f42f2342c5f in QThread::exec (this=this@entry=0x1b1f660) at thread/qthread.cpp:537
#10 0x00007f42f2427823 in QInotifyFileSystemWatcherEngine::run (this=0x1b1f660) at io/qfilesystemwatcher_inotify.cpp:265
#11 0x00007f42f234532f in QThreadPrivate::start (arg=0x1b1f660) at thread/qthread_unix.cpp:349
#12 0x00007f42ee81c182 in start_thread (arg=0x7f42c4b4b700) at pthread_create.c:312
#13 0x00007f42f104812d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111

Thread 1 (Thread 0x7f42f37b37c0 (LWP 2610)):
[KCrash Handler]
#6  KScreen::Mode::size (this=this@entry=0x0) at /build/buildd/libkscreen-1.0.2/src/mode.cpp:102
#7  0x00007f42cfdf5249 in Generator::biggestOutput (this=this@entry=0x1c84930, outputs=...) at /build/buildd/kscreen-1.0.2.1/kded/generator.cpp:474
#8  0x00007f42cfdf5b90 in Generator::laptop (this=this@entry=0x1c84930, outputs=...) at /build/buildd/kscreen-1.0.2.1/kded/generator.cpp:354
#9  0x00007f42cfdf79eb in Generator::idealConfig (this=0x1c84930) at /build/buildd/kscreen-1.0.2.1/kded/generator.cpp:88
#10 0x00007f42cfdef307 in KScreenDaemon::applyIdealConfig (this=this@entry=0x1c81b70) at /build/buildd/kscreen-1.0.2.1/kded/daemon.cpp:118
#11 0x00007f42cfdef53e in KScreenDaemon::applyConfig (this=0x1c81b70) at /build/buildd/kscreen-1.0.2.1/kded/daemon.cpp:98
#12 0x00007f42f245b87a in QMetaObject::activate (sender=0x1c84930, m=<optimized out>, local_signal_index=<optimized out>, argv=0x0) at kernel/qobject.cpp:3539
#13 0x00007f42f245b87a in QMetaObject::activate (sender=sender@entry=0x1c82b90, m=m@entry=0x7f42cfffeb40 <Device::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3539
#14 0x00007f42cfdf8d34 in ready (this=0x1c82b90) at /build/buildd/kscreen-1.0.2.1/obj-x86_64-linux-gnu/kded/device.moc:113
#15 Device::setReady (this=this@entry=0x1c82b90) at /build/buildd/kscreen-1.0.2.1/kded/device.cpp:80
#16 0x00007f42cfdf9d0e in setReady (this=0x1c82b90) at /build/buildd/kscreen-1.0.2.1/kded/device.cpp:148
#17 fetchIsDocked (this=0x1c82b90) at /build/buildd/kscreen-1.0.2.1/kded/device.cpp:157
#18 Device::isLidClosedFetched (this=0x1c82b90, watcher=0x1e57170) at /build/buildd/kscreen-1.0.2.1/kded/device.cpp:152
#19 0x00007f42f245b87a in QMetaObject::activate (sender=0x1e57170, m=m@entry=0x7f42efa1f640 <QDBusPendingCallWatcher::staticMetaObject>, local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x7fff595e0be0) at kernel/qobject.cpp:3539
#20 0x00007f42ef8010ef in QDBusPendingCallWatcher::finished (this=<optimized out>, _t1=0x1e57170) at .moc/release-shared/moc_qdbuspendingcall.cpp:105
#21 0x00007f42f245fc1e in QObject::event (this=0x1e57170, e=<optimized out>) at kernel/qobject.cpp:1194
#22 0x00007f42f17e0e2c in QApplicationPrivate::notify_helper (this=this@entry=0x1923530, receiver=receiver@entry=0x1e57170, e=e@entry=0x1c7f9a0) at kernel/qapplication.cpp:4567
#23 0x00007f42f17e74a0 in QApplication::notify (this=this@entry=0x7fff595e1330, receiver=receiver@entry=0x1e57170, e=e@entry=0x1c7f9a0) at kernel/qapplication.cpp:4353
#24 0x00007f42f31c6b9a in KApplication::notify (this=0x7fff595e1330, receiver=0x1e57170, event=0x1c7f9a0) at ../../kdeui/kernel/kapplication.cpp:311
#25 0x00007f42f24474dd in QCoreApplication::notifyInternal (this=0x7fff595e1330, receiver=receiver@entry=0x1e57170, event=event@entry=0x1c7f9a0) at kernel/qcoreapplication.cpp:953
#26 0x00007f42f244ab3d in sendEvent (event=0x1c7f9a0, receiver=0x1e57170) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:231
#27 QCoreApplicationPrivate::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0, data=0x1880150) at kernel/qcoreapplication.cpp:1577
#28 0x00007f42f244afe3 in QCoreApplication::sendPostedEvents (receiver=receiver@entry=0x0, event_type=event_type@entry=0) at kernel/qcoreapplication.cpp:1470
#29 0x00007f42f2474f83 in sendPostedEvents () at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:236
#30 postEventSourceDispatch (s=0x1923a20) at kernel/qeventdispatcher_glib.cpp:287
#31 0x00007f42ee139e04 in g_main_dispatch (context=0x19238b0) at /build/buildd/glib2.0-2.39.91/./glib/gmain.c:3064
#32 g_main_context_dispatch (context=context@entry=0x19238b0) at /build/buildd/glib2.0-2.39.91/./glib/gmain.c:3663
#33 0x00007f42ee13a048 in g_main_context_iterate (context=context@entry=0x19238b0, block=block@entry=1, dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.39.91/./glib/gmain.c:3734
#34 0x00007f42ee13a0ec in g_main_context_iteration (context=0x19238b0, may_block=1) at /build/buildd/glib2.0-2.39.91/./glib/gmain.c:3795
#35 0x00007f42f24747a1 in QEventDispatcherGlib::processEvents (this=0x18826d0, flags=...) at kernel/qeventdispatcher_glib.cpp:434
#36 0x00007f42f1882bb6 in QGuiEventDispatcherGlib::processEvents (this=<optimized out>, flags=...) at kernel/qguieventdispatcher_glib.cpp:204
#37 0x00007f42f24460af in QEventLoop::processEvents (this=this@entry=0x7fff595e1200, flags=...) at kernel/qeventloop.cpp:149
#38 0x00007f42f24463a5 in QEventLoop::exec (this=this@entry=0x7fff595e1200, flags=...) at kernel/qeventloop.cpp:204
#39 0x00007f42f244bb79 in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1225
#40 0x00007f42f17df37c in QApplication::exec () at kernel/qapplication.cpp:3828
#41 0x00007f42dd3e494b in kdemain (argc=1, argv=0x1901060) at ../../kded/kded.cpp:925
#42 0x00000000004083ee in launch (argc=argc@entry=1, _name=_name@entry=0x40afc7 "kded4", args=args@entry=0x0, cwd=cwd@entry=0x0, envc=envc@entry=0, envs=<optimized out>, envs@entry=0x0, reset_env=reset_env@entry=false, tty=tty@entry=0x0, avoid_loops=avoid_loops@entry=false, startup_id_str=startup_id_str@entry=0x40ae56 "0") at ../../kinit/kinit.cpp:738
#43 0x00000000004059a3 in main (argc=4, argv=<optimized out>, envp=0x7fff595e1a90) at ../../kinit/kinit.cpp:1853