Sometimes when I resume my laptop from suspend to RAM, I get an xmessage window saying "Could not start ksmserver. Check your installation."

I also switched my monitors from no external monitors to 3 external monitors. Their relative layout was wrong but they all worked.

This may be a duplicate, but I've searched and can't find anything corresponding to my backtrace:

Application: ksmserver (ksmserver), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7f0542d53940 (LWP 26467))]

Thread 2 (Thread 0x7f052a308700 (LWP 26469)):
#0  0x00007f054281470d in poll () at ../sysdeps/unix/syscall-template.S:84
#1  0x00007f0537d5138c in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007f0537d5149c in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007f053dbb237b in QEventDispatcherGlib::processEvents (this=0x7f051c0008e0, flags=...) at kernel/qeventdispatcher_glib.cpp:419
#4  0x00007f053db5affa in QEventLoop::exec (this=this@entry=0x7f052a307c50, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#5  0x00007f053d9839e4 in QThread::exec (this=this@entry=0x7f0542f15d40 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread.cpp:500
#6  0x00007f0542ea2515 in QDBusConnectionManager::run (this=0x7f0542f15d40 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at qdbusconnection.cpp:189
#7  0x00007f053d988808 in QThreadPrivate::start (arg=0x7f0542f15d40 <(anonymous namespace)::Q_QGS__q_manager::innerFunction()::holder>) at thread/qthread_unix.cpp:341
#8  0x00007f05388dd6ba in start_thread (arg=0x7f052a308700) at pthread_create.c:333
#9  0x00007f05428203dd in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Thread 1 (Thread 0x7f0542d53940 (LWP 26467)):
[KCrash Handler]
#4  0x00007f054279d532 in __GI___libc_free (mem=0xa7a690) at malloc.c:2967
#5  0x00007f053d989b31 in QArrayData::deallocate (data=<optimized out>, objectSize=objectSize@entry=2, alignment=alignment@entry=8) at tools/qarraydata.cpp:142
#6  0x00007f0542af2cd7 in QTypedArrayData<unsigned short>::deallocate (data=<optimized out>) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qarraydata.h:222
#7  QString::~QString (this=0xa35620, __in_chrg=<optimized out>) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qstring.h:1065
#8  QList<QString>::node_destruct (this=<optimized out>, to=0xa35620, from=0xa35620) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qlist.h:486
#9  QList<QString>::dealloc (data=0xa35610, this=0x7fffb2d95d90) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qlist.h:855
#10 0x00007f0542af5dc8 in QList<QString>::~QList (this=this@entry=0x7fffb2d95d90, __in_chrg=<optimized out>) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qlist.h:817
#11 0x00007f0542b0844b in QStringList::~QStringList (this=0x7fffb2d95d90, __in_chrg=<optimized out>) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qstringlist.h:93
#12 KSMServer::<lambda(int)>::operator() (exitCode=1, __closure=0xa5a9a0) at /build/plasma-workspace-oCGd_j/plasma-workspace-5.8.8/ksmserver/startup.cpp:692
#13 QtPrivate::FunctorCall<QtPrivate::IndexesList<0>, QtPrivate::List<int>, void, KSMServer::slotAutoStart()::<lambda(int)> >::call (arg=<optimized out>, f=...) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qobjectdefs_impl.h:495
#14 QtPrivate::Functor<KSMServer::slotAutoStart()::<lambda(int)>, 1>::call<QtPrivate::List<int>, void> (arg=<optimized out>, f=...) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qobjectdefs_impl.h:552
#15 QtPrivate::QFunctorSlotObject<KSMServer::slotAutoStart()::<lambda(int)>, 1, QtPrivate::List<int>, void>::impl(int, QtPrivate::QSlotObjectBase *, QObject *, void **, bool *) (which=<optimized out>, this_=0xa5a990, r=<optimized out>, a=<optimized out>, ret=<optimized out>) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qobject_impl.h:192
#16 0x00007f053db89c24 in QtPrivate::QSlotObjectBase::call (a=0x7fffb2d95f40, r=0xa270a0, this=<optimized out>) at ../../include/QtCore/../../src/corelib/kernel/qobject_impl.h:124
#17 QMetaObject::activate (sender=sender@entry=0xa270a0, signalOffset=<optimized out>, local_signal_index=local_signal_index@entry=1, argv=argv@entry=0x7fffb2d95f40) at kernel/qobject.cpp:3715
#18 0x00007f053db8a1b7 in QMetaObject::activate (sender=sender@entry=0xa270a0, m=m@entry=0x7f053dda11a0 <QProcess::staticMetaObject>, local_signal_index=local_signal_index@entry=1, argv=argv@entry=0x7fffb2d95f40) at kernel/qobject.cpp:3595
#19 0x00007f053da8f171 in QProcess::finished (this=this@entry=0xa270a0, _t1=1) at .moc/moc_qprocess.cpp:325
#20 0x00007f053da9247f in QProcessPrivate::_q_processDied (this=this@entry=0xa974a0) at io/qprocess.cpp:1133
#21 0x00007f053daf1f3f in QProcessPrivate::waitForFinished (this=this@entry=0xa974a0, msecs=msecs@entry=30000) at io/qprocess_unix.cpp:923
#22 0x00007f053da91f1f in QProcess::waitForFinished (this=this@entry=0xa270a0, msecs=msecs@entry=30000) at io/qprocess.cpp:1876
#23 0x00007f053da92ce5 in QProcess::~QProcess (this=0xa270a0, __in_chrg=<optimized out>) at io/qprocess.cpp:1216
#24 0x00007f053f1db759 in KProcess::~KProcess() () from /usr/lib/x86_64-linux-gnu/libKF5CoreAddons.so.5
#25 0x00007f053db88053 in QObjectPrivate::deleteChildren (this=this@entry=0xa0b630) at kernel/qobject.cpp:1963
#26 0x00007f053db91094 in QObject::~QObject (this=<optimized out>, __in_chrg=<optimized out>) at kernel/qobject.cpp:1034
#27 0x00007f0542afcc49 in KSMServer::~KSMServer (this=0xa1f5e0, __in_chrg=<optimized out>) at /build/plasma-workspace-oCGd_j/plasma-workspace-5.8.8/ksmserver/server.cpp:733
#28 0x00007f0542af916c in sighandler (sig=<optimized out>) at /build/plasma-workspace-oCGd_j/plasma-workspace-5.8.8/ksmserver/server.cpp:539
#29 <signal handler called>
#30 0x00007f054281470d in poll () at ../sysdeps/unix/syscall-template.S:84
#31 0x00007f0537d5138c in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#32 0x00007f0537d5149c in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#33 0x00007f053dbb237b in QEventDispatcherGlib::processEvents (this=0x9e7d50, flags=...) at kernel/qeventdispatcher_glib.cpp:419
#34 0x00007f053db5affa in QEventLoop::exec (this=this@entry=0x7fffb2d96a40, flags=..., flags@entry=...) at kernel/qeventloop.cpp:204
#35 0x00007f053db636bc in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1285
#36 0x00007f053dea37cc in QGuiApplication::exec () at kernel/qguiapplication.cpp:1607
#37 0x00007f053e48fac5 in QApplication::exec () at kernel/qapplication.cpp:2979
#38 0x00007f0542af56b9 in kdemain (argc=1, argv=<optimized out>) at /build/plasma-workspace-oCGd_j/plasma-workspace-5.8.8/ksmserver/main.cpp:350
#39 0x00007f0542739830 in __libc_start_main (main=0x400780 <main(int, char**)>, argc=1, argv=0x7fffb2d96cf8, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7fffb2d96ce8) at ../csu/libc-start.c:291
#40 0x00000000004007b9 in _start ()


I also see an error in /var/log/syslog that might be relevant:

Nov 29 10:49:03 pc-5000-cl kernel: [142088.895417] kscreen_backend[26461]: segfault at 8 ip 00007f2ae09c768e sp 00007ffe784878d0 error 4 in KSC_XRandR.so[7f2ae09c0000+22000]

This does not happen every time I suspend and move my laptop between these same hardware configurations (no external vs. 3 external monitors).