Here is somewhat a longer trace (running as normal user):
Process 23933 (lt-octave-gui) of user 1001 dumped core.
Stack trace of thread 24145:
#0 0x00007fb291116641 _ZN16QCoreApplication9postEventEP7QObjectP6QEventi (libQt5Core.so.5)
#1 0x00007fb29113b85f _ZN11QMetaObject8activateEP7QObjectiiPPv (libQt5Core.so.5)
#2 0x00007fb293ed32e1 _ZN18octave_interpreter22octave_finished_signalEi (liboctgui.so.2)
#3 0x00007fb293ea3391 _ZN18octave_interpreter7executeEv (liboctgui.so.2)
#4 0x00007fb29113c91a _ZN7QObject5eventEP6QEvent (libQt5Core.so.5)
#5 0x00007fb291d7c6ac _ZN19QApplicationPrivate13notify_helperEP7QObjectP6QEvent (libQt5Widgets.so.5)
#6 0x00007fb291d83ef4 _ZN12QApplication6notifyEP7QObjectP6QEvent (libQt5Widgets.so.5)
#7 0x00007fb291113367 _ZN16QCoreApplication15notifyInternal2EP7QObjectP6QEvent (libQt5Core.so.5)
#8 0x00007fb291115aeb _ZN23QCoreApplicationPrivate16sendPostedEventsEP7QObjectiP11QThreadData (libQt5Core.so.5)
#9 0x00007fb291164553 _ZL23postEventSourceDispatchP8_GSourcePFiPvES1_ (libQt5Core.so.5)
#10 0x00007fb282a2bbb7 g_main_context_dispatch (libglib-2.0.so.0)
#11 0x00007fb282a2bf60 g_main_context_iterate.isra.25 (libglib-2.0.so.0)
#12 0x00007fb282a2bfec g_main_context_iteration (libglib-2.0.so.0)
#13 0x00007fb29116433f _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt5Core.so.5)
#14 0x00007fb2911120ea _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt5Core.so.5)
#15 0x00007fb290f638ba _ZN7QThread4execEv (libQt5Core.so.5)
#16 0x00007fb290f67b92 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5)
#17 0x00007fb28895761b start_thread (libpthread.so.0)
#18 0x00007fb28868491f __clone (libc.so.6)
Stack trace of thread 23933:
#0 0x00007fb28895dc4b pthread_cond_wait@@GLIBC_2.3.2 (libpthread.so.0)
#1 0x00007fb290f682eb _ZN14QWaitCondition4waitEP6QMutexm (libQt5Core.so.5)
#2 0x00007fb290f6231b _ZN10QSemaphore7acquireEi (libQt5Core.so.5)
#3 0x00007fb29113ba3b _ZN11QMetaObject8activateEP7QObjectiiPPv (libQt5Core.so.5)
#4 0x00007fb29113c2df _ZN7QObject9destroyedEPS_ (libQt5Core.so.5)
#5 0x00007fb291142ef9 _ZN7QObjectD1Ev (libQt5Core.so.5)
#6 0x00007fb25d421bb9 _ZN7Adwaita5StyleD0Ev (adwaita.so)
#7 0x00007fb291d7d033 _ZN12QApplicationD1Ev (libQt5Widgets.so.5)
#8 0x00007fb293ef0fd8 _ZN6octave15gui_application7executeEv (liboctgui.so.2)
#9 0x000000000040134c main (lt-octave-gui)
#10 0x00007fb28858e00a __libc_start_main (libc.so.6)
#11 0x000000000040160a _start (lt-octave-gui)
Stack trace of thread 24083:
#0 0x00007fb28867836b __poll (libc.so.6)
#1 0x00007fb282a2bed9 g_main_context_iterate.isra.25 (libglib-2.0.so.0)
#2 0x00007fb282a2c272 g_main_loop_run (libglib-2.0.so.0)
#3 0x00007fb263170b36 gdbus_shared_thread_func (libgio-2.0.so.0)
#4 0x00007fb282a534c6 g_thread_proxy (libglib-2.0.so.0)
#5 0x00007fb28895761b start_thread (libpthread.so.0)
#6 0x00007fb28868491f __clone (libc.so.6)
Stack trace of thread 24041:
#0 0x00007fb28867836b __poll (libc.so.6)
#1 0x00007fb286a90fe7 _xcb_conn_wait (libxcb.so.1)
#2 0x00007fb286a92dda xcb_wait_for_event (libxcb.so.1)
#3 0x00007fb26c065a49 _ZN15QXcbEventReader3runEv (libQt5XcbQpa.so.5)
#4 0x00007fb290f67b92 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5)
#5 0x00007fb28895761b start_thread (libpthread.so.0)
#6 0x00007fb28868491f __clone (libc.so.6)
Stack trace of thread 24144:
#0 0x00007fb28867836b __poll (libc.so.6)
#1 0x00007fb282a2bed9 g_main_context_iterate.isra.25 (libglib-2.0.so.0)
#2 0x00007fb282a2bfec g_main_context_iteration (libglib-2.0.so.0)
#3 0x00007fb29116433f _ZN20QEventDispatcherGlib13processEventsE6QFlagsIN10QEventLoop17ProcessEventsFlagEE (libQt5Core.so.5)
#4 0x00007fb2911120ea _ZN10QEventLoop4execE6QFlagsINS_17ProcessEventsFlagEE (libQt5Core.so.5)
#5 0x00007fb290f638ba _ZN7QThread4execEv (libQt5Core.so.5)
#6 0x00007fb26bdb7479 _ZN22QDBusConnectionManager3runEv (libQt5DBus.so.5)
#7 0x00007fb290f67b92 _ZN14QThreadPrivate5startEPv (libQt5Core.so.5)
#8 0x00007fb28895761b start_thread (libpthread.so.0)
#9 0x00007fb28868491f __clone (libc.so.6)
Stack trace of thread 24076:
#0 0x00007fb28867836b __poll (libc.so.6)
#1 0x00007fb282a2bed9 g_main_context_iterate.isra.25 (libglib-2.0.so.0)
#2 0x00007fb282a2bfec g_main_context_iteration (libglib-2.0.so.0)
#3 0x00007fb26055d42d dconf_gdbus_worker_thread (libdconfsettings.so)
#4 0x00007fb282a534c6 g_thread_proxy (libglib-2.0.so.0)
#5 0x00007fb28895761b start_thread (libpthread.so.0)
#6 0x00007fb28868491f __clone (libc.so.6)
Stack trace of thread 24146:
#0 0x00007fb288962616 sigwait (libpthread.so.0)
#1 0x00007fb2903a4d12 signal_watcher (liboctave.so.4)
#2 0x00007fb28895761b start_thread (libpthread.so.0)
#3 0x00007fb28868491f __clone (libc.so.6)
Stack trace of thread 24078:
#0 0x00007fb28867836b __poll (libc.so.6)
#1 0x00007fb282a2bed9 g_main_context_iterate.isra.25 (libglib-2.0.so.0)
#2 0x00007fb282a2bfec g_main_context_iteration (libglib-2.0.so.0)
#3 0x00007fb282a2c031 glib_worker_main (libglib-2.0.so.0)
#4 0x00007fb282a534c6 g_thread_proxy (libglib-2.0.so.0)
#5 0x00007fb28895761b start_thread (libpthread.so.0)
#6 0x00007fb28868491f __clone (libc.so.6)
Dmitri.
--