Application: cantor (18.08.1)

Qt Version: 5.11.2
Frameworks Version: 5.51.0
Operating System: Linux 4.18.0-3-amd64 x86_64
Distribution: Debian GNU/Linux buster/sid

-- Information about the crash:
Cantor version 18.08.1 and SageMath version 8.3 on Debian Buster.

The crash can be reproduced every time.

-- Backtrace:
Application: Cantor (cantor), signal: Segmentation fault
Using host libthread_db library "/lib/x86_64-linux-gnu/libthread_db.so.1".
[Current thread is 1 (Thread 0x7fc23f3aa300 (LWP 32593))]

Thread 4 (Thread 0x7fc234cfd700 (LWP 32596)):
#0  0x00007fc243192e6c in futex_wait_cancelable (private=<optimized out>, expected=0, futex_word=0x56222a771a08) at ../sysdeps/unix/sysv/linux/futex-internal.h:88
#1  0x00007fc243192e6c in __pthread_cond_wait_common (abstime=0x0, mutex=0x56222a7719b8, cond=0x56222a7719e0) at pthread_cond_wait.c:502
#2  0x00007fc243192e6c in __pthread_cond_wait (cond=0x56222a7719e0, mutex=0x56222a7719b8) at pthread_cond_wait.c:655
#3  0x00007fc2353debab in  () at /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#4  0x00007fc2353de8d7 in  () at /usr/lib/x86_64-linux-gnu/dri/i965_dri.so
#5  0x00007fc24318cf2a in start_thread (arg=0x7fc234cfd700) at pthread_create.c:463
#6  0x00007fc244008edf in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 3 (Thread 0x7fc237430700 (LWP 32595)):
#0  0x00007fc243ffe739 in __GI___poll (fds=0x7fc230004230, nfds=2, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007fc242612e46 in  () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#2  0x00007fc242612f6c in g_main_context_iteration () at /usr/lib/x86_64-linux-gnu/libglib-2.0.so.0
#3  0x00007fc244527d13 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#4  0x00007fc2444d4d0b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007fc2443240c6 in QThread::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#6  0x00007fc24358e545 in  () at /usr/lib/x86_64-linux-gnu/libQt5DBus.so.5
#7  0x00007fc24432dc97 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#8  0x00007fc24318cf2a in start_thread (arg=0x7fc237430700) at pthread_create.c:463
#9  0x00007fc244008edf in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 2 (Thread 0x7fc23dd2c700 (LWP 32594)):
#0  0x00007fc243ffe739 in __GI___poll (fds=0x7fc23dd2bcb8, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
#1  0x00007fc241e7dcf7 in  () at /usr/lib/x86_64-linux-gnu/libxcb.so.1
#2  0x00007fc241e7f91a in xcb_wait_for_event () at /usr/lib/x86_64-linux-gnu/libxcb.so.1
#3  0x00007fc23eebe519 in  () at /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#4  0x00007fc24432dc97 in  () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#5  0x00007fc24318cf2a in start_thread (arg=0x7fc23dd2c700) at pthread_create.c:463
#6  0x00007fc244008edf in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

Thread 1 (Thread 0x7fc23f3aa300 (LWP 32593)):
[KCrash Handler]
#6  0x00007fc2443a57ac in QString::toInt(bool*, int) const () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007fc23449f07d in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/cantor/backends/cantor_sagebackend.so
#8  0x00007fc23449f3f1 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/cantor/backends/cantor_sagebackend.so
#9  0x00007fc22ec42621 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/libcantorpart.so
#10 0x00007fc22ec42c65 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/libcantorpart.so
#11 0x00007fc22ec78c95 in  () at /usr/lib/x86_64-linux-gnu/qt5/plugins/libcantorpart.so
#12 0x00007fc2444ff28b in QMetaObject::activate(QObject*, int, int, void**) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#13 0x00007fc244e45ee2 in QAction::triggered(bool) () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#14 0x00007fc244e484f0 in QAction::activate(QAction::ActionEvent) () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#15 0x00007fc244e48da4 in QAction::event(QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#16 0x00007fc244e4c491 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#17 0x00007fc244e53ad0 in QApplication::notify(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Widgets.so.5
#18 0x00007fc2444d6039 in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#19 0x00007fc2448aa6d3 in QShortcutMap::dispatchEvent(QKeyEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#20 0x00007fc2448aa7ab in QShortcutMap::tryShortcut(QKeyEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#21 0x00007fc24485fa86 in QWindowSystemInterface::handleShortcutEvent(QWindow*, unsigned long, int, QFlags<Qt::KeyboardModifier>, unsigned int, unsigned int, unsigned int, QString const&, bool, unsigned short) () at /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#22 0x00007fc24487c2ad in QGuiApplicationPrivate::processKeyEvent(QWindowSystemInterfacePrivate::KeyEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#23 0x00007fc244881a05 in QGuiApplicationPrivate::processWindowSystemEvent(QWindowSystemInterfacePrivate::WindowSystemEvent*) () at /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#24 0x00007fc24485bd8b in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
#25 0x00007fc23ef5185b in  () at /usr/lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#26 0x00007fc2444d4d0b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#27 0x00007fc2444dce82 in QCoreApplication::exec() () at /usr/lib/x86_64-linux-gnu/libQt5Core.so.5
#28 0x0000562229b56d17 in  ()
#29 0x00007fc243f33b17 in __libc_start_main (main=0x562229b56040, argc=5, argv=0x7ffff7089f58, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffff7089f48) at ../csu/libc-start.c:310
#30 0x0000562229b571ca in _start ()
[Inferior 1 (process 32593) detached]

Reported using DrKonqi