.
Thread 1 (Thread 0x7fc047b437c0 (LWP 5969)):
#0  0x00007fc045decd27 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
        resultvar = 0
        pid = 5969
        selftid = 5969
#1  0x00007fc045dee418 in __GI_abort () at abort.c:89
        save_stage = 2
        act = {__sigaction_handler = {sa_handler = 0x1034600, sa_sigaction = 0x1034600}, sa_mask = {__val = {1, 0, 140463811528023, 140733193388033, 0, 3, 140463782481192, 17101088, 0, 140463790034240, 140463811556661, 140463813441440, 140463813441440, 140463813443792, 140463813443792, 1}}, sa_flags = 1202995408, sa_restorer = 0x6f6e20646c756f43}
        sigs = {__val = {32, 0 <repeats 15 times>}}
#2  0x00007fc046206495 in qt_message_fatal (context=..., message=...) at global/qlogging.cpp:1340
No locals.
#3  QMessageLogger::fatal (this=this@entry=0x7fff97a83290, msg=msg@entry=0x7fc03429aa20 "QXcbConnection: Could not connect to display %s") at global/qlogging.cpp:669
        message = {static null = {<No data fields>}, d = 0x104f590}
        ap = {{gp_offset = 24, fp_offset = 48, overflow_arg_area = 0x7fff97a83280, reg_save_area = 0x7fff97a831c0}}
#4  0x00007fc0342408f2 in QXcbConnection::QXcbConnection (this=0x104f120, nativeInterface=0x1034600, canGrabServer=<optimized out>, displayName=0x0) at qxcbconnection.cpp:322
        dpy = 0x0
        extensions = {0x14200000001, 0x7fc034299dc0, 0x7fc03429b8c0 <QXcbConnection::QXcbConnection(QXcbNativeInterface*, bool, char const*)::__PRETTY_FUNCTION__>, 0x7fc034299872, 0x7fff97a8367c, 0xfa0f18, 0x104f120, 0x7fc04549fca0, 0x7fc04238fc60}
#5  0x00007fc03424250e in QXcbIntegration::QXcbIntegration (this=0x10357b0, parameters=..., argc=@0x7fff97a8367c: 2, argv=0x102dde0) at qxcbintegration.cpp:161
        canGrab = true
        displayName = 0x0
        canNotGrabEnv = false
#6  0x00007fc0342530db in QXcbIntegrationPlugin::create (this=<optimized out>, system=..., parameters=..., argc=@0x7fff97a8367c: 2, argv=0x102dde0) at qxcbmain.cpp:58
No locals.
#7  0x00007fc047332771 in loadIntegration (argv=0x102dde0, argc=@0x7fff97a8367c: 2, parameters=..., key=..., loader=0x7fc04795ef40 <_ZZN12_GLOBAL__N_112Q_QGS_loader13innerFunctionEvE6holder>) at kernel/qplatformintegrationfactory.cpp:64
        result = <optimized out>
        index = <optimized out>
#8  QPlatformIntegrationFactory::create (platform=..., paramList=..., argc=@0x7fff97a8367c: 2, argv=argv@entry=0x102dde0, platformPluginPath=...) at kernel/qplatformintegrationfactory.cpp:81
No locals.
#9  0x00007fc04733da61 in init_platform (argv=0x102dde0, argc=@0x7fff97a8367c: 2, platformThemeName=..., platformPluginPath=..., pluginArgument=...) at kernel/qguiapplication.cpp:980
        arguments = {<QList<QString>> = {{p = {static shared_null = {ref = {atomic = {_q_value = -1}}, alloc = 0, begin = 0, end = 0, array = {0x0}}, d = 0xfeb140}, d = 0xfeb140}}, <No data fields>}
        name = {static null = {<No data fields>}, d = 0x102dad0}
        argumentsKey = {static null = {<No data fields>}, d = 0xfea3c0}
        themeNames = {<QList<QString>> = {{p = {static shared_null = {ref = {atomic = {_q_value = -1}}, alloc = 0, begin = 0, end = 0, array = {0x0}}, d = 0xfe93a0}, d = 0xfe93a0}}, <No data fields>}
#10 QGuiApplicationPrivate::createPlatformIntegration (this=<optimized out>) at kernel/qguiapplication.cpp:1128
        platformName = {d = 0x102d500}
        platformNameEnv = {d = 0x7fc0464f0d40 <QArrayData::shared_null>}
        platformThemeName = {static null = {<No data fields>}, d = 0xfea330}
        platformPluginPath = {static null = {<No data fields>}, d = 0x7fc0464f0ce0 <qt_array>}
        j = <optimized out>
#11 0x00007fc04733e5ad in QGuiApplicationPrivate::createEventDispatcher (this=<optimized out>) at kernel/qguiapplication.cpp:1143
No locals.
#12 0x00007fc046442c21 in QCoreApplication::init (this=this@entry=0x7fff97a836b0) at kernel/qcoreapplication.cpp:734
        d = 0x102f5f0
#13 0x00007fc046442c96 in QCoreApplication::QCoreApplication (this=0x7fff97a836b0, p=...) at kernel/qcoreapplication.cpp:657
No locals.
#14 0x00007fc04733f3ad in QGuiApplication::QGuiApplication (this=0x7fff97a836b0, argc=@0x7fff97a8367c: 2, argv=0x102dde0, flags=328448) at kernel/qguiapplication.cpp:532
No locals.
#15 0x00007fc0344d13eb in kdemain () from /usr/lib/x86_64-linux-gnu/libkdeinit5_klauncher.so
No symbol table info available.
#16 0x0000000000408714 in ?? ()
No symbol table info available.
#17 0x0000000000409817 in ?? ()
No symbol table info available.
#18 0x0000000000405856 in main ()
No symbol table info available.