Total Qt Creator freeze during editing causing Ubuntu freeze and logout

I have a large C++ project which was building fine until I started a major refactoring of it. My refactoring process consists of editing source code files, moving big chunks of files between source files and editing text etc.. During editing Qt is doing some kind of background rescans of the text for context help and things.

What has happened recently is the mouse pointer gets laggy and eventually Qt creator stops responding totally. After about 30 seconds I get a black screen and then the Ubuntu login screen reappears. I then have to log back into Ubuntu, run up Qt again and resume editing.

I believe this may be something to do with the fact most of the source files have spanish words in them. The Qt editor sometimes says "Error:... with "UTF-8"-encoding. Editing not possible", so I have to click on the righthand "Select Encoding" button to select a new text encoding, then click on the "Reload with Encoding" button. It is usually shortly after that this problem occurs.

Below is part of a core crash dump I found in /var/crash... The entire file is 48MB in size.

{0x0, 0x0, 0x0, 0x0}, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
         not_first_call = <optimised out>
 #9  0x00007f00c2761850 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
 .
 Thread 2 (Thread 0x7f008aed2640 (LWP 5540)):
 #0  0x00007f00c2753bcf in {}GI{}_poll (fds=0x7f007c003e40, nfds=1, timeout=-1) at ../sysdeps/unix/sysv/linux/poll.c:29
         sc_ret = -516
         sc_cancel_oldtype = 0
 #1  0x00007f00bfa31256 in  () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
 #2  0x00007f00bf9d93e3 in g_main_context_iteration () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
 #3  0x00007f00c2fa26da in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Core.so.6
 #4  0x00007f00c2d07023 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Core.so.6
 #5  0x00007f00c2dfb0dc in QThread::exec() () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Core.so.6
 #6  0x00007f00c2e9070d in  () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Core.so.6
 #7  0x00007f00c26cfac3 in start_thread (arg=<optimised out>) at ./nptl/pthread_create.c:442
         ret = <optimised out>
         pd = <optimised out>
         unwind_buf = {cancel_jmp_buf = jmp_buf = {140736686998032, -4049014117157219162, 139640307525184, 17, 139641238648784, 140736686998384, 4165291748371551398, 4165415985572959398}, mask_was_saved = 0, priv = {pad = {0x0, 0x0, 0x0, 0x0}

, data = {prev = 0x0, cleanup = 0x0, canceltype = 0}}}
         not_first_call = <optimised out>
 #8  0x00007f00c2761850 in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81
 .
 Thread 1 (Thread 0x7f00bf1509c0 (LWP 5522)):
 #0  0x00007f00b476064c in TextEditor::TextEditorWidget::selectEncoding() () at /opt/Qt/Tools/QtCreator/lib/qtcreator/plugins/libTextEditor.so
 #1  0x00007f00c2d57cd2 in  () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Core.so.6
 #2  0x00007f00c4113932 in QAbstractButton::clicked(bool) () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Widgets.so.6
 #3  0x00007f00c4113b7a in  () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Widgets.so.6
 #4  0x00007f00c4115650 in  () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Widgets.so.6
 #5  0x00007f00c41158ce in QAbstractButton::mouseReleaseEvent(QMouseEvent*) () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Widgets.so.6
 #6  0x00007f00c421faea in QToolButton::mouseReleaseEvent(QMouseEvent*) () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Widgets.so.6
 #7  0x00007f00c404ac1e in QWidget::event(QEvent*) () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Widgets.so.6
 #8  0x00007f00c3ff7012 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Widgets.so.6
 #9  0x00007f00c3fff940 in QApplication::notify(QObject*, QEvent*) () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Widgets.so.6
 #10 0x00007f00c2cfb6da in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Core.so.6
 #11 0x00007f00c3ffec90 in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&, bool, bool) () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Widgets.so.6
 #12 0x00007f00c405cae1 in  () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Widgets.so.6
 #13 0x00007f00c405f74b in  () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Widgets.so.6
 #14 0x00007f00c3ff7012 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Widgets.so.6
 #15 0x00007f00c2cfb6da in QCoreApplication::notifyInternal2(QObject*, QEvent*) () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Core.so.6
 #16 0x00007f00c3660670 in QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::MouseEvent*) () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Gui.so.6
 #17 0x00007f00c36b820c in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Gui.so.6
 #18 0x00007f00beb6e7fa in  () at /opt/Qt/Tools/QtCreator/lib/Qt/plugins/platforms/../../lib/libQt6XcbQpa.so.6
 #19 0x00007f00bf9dbd3b in g_main_context_dispatch () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
 #20 0x00007f00bfa312b8 in  () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
 #21 0x00007f00bf9d93e3 in g_main_context_iteration () at /lib/x86_64-linux-gnu/libglib-2.0.so.0
 #22 0x00007f00c2fa26da in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Core.so.6
 #23 0x00007f00c2d07023 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Core.so.6
 #24 0x00007f00c2d03aee in QCoreApplication::exec() () at /opt/Qt/Tools/QtCreator/bin/../lib/Qt/lib/libQt6Core.so.6
 #25 0x000000000040e914 in  ()
 #26 0x00007f00c2664d90 in __libc_start_call_main (main=main@entry=0x40b320, argc=argc@entry=1, argv=argv@entry=0x7fffd03c51e8) at ../sysdeps/nptl/libc_start_call_main.h:58
         self = <optimised out>
         result = <optimised out>
         unwind_buf = {cancel_jmp_buf = {{jmp_buf =

{0, -4049014117157088090, 140736687002088, 4240160, 0, 139641277354048, 4048915716266349734, 4165416034578551974}

, mask_was_saved = 0}}, priv = {pad =

{0x0, 0x0, 0x7fffd03c51e8, 0x0}

, data = {prev = 0x0, cleanup = 0x0, canceltype = -801353240}}}
         not_first_call = <optimised out>
 #27 0x00007f00c2664e40 in __libc_start_main_impl (main=0x40b320, argc=1, argv=0x7fffd03c51e8, init=<optimised out>, fini=<optimised out>, rtld_fini=<optimised out>, stack_end=0x7fffd03c51d8) at ../csu/libc-start.c:392
 #28 0x000000000040f06e in  ()
Title: qtcreator crashed with SIGSEGV in TextEditor::TextEditorWidget::selectEncoding()