Application: kwin_x11 (5.19.5)

Qt Version: 5.14.2
Frameworks Version: 5.74.0
Operating System: Linux 5.8.0-55-generic x86_64
Windowing system: X11
Distribution: Ubuntu 20.10

-- Information about the crash:
- What I was doing when the application crashed:

I had a few VS Code windows open, a Konsole window, and Firefox.  I use Alt+Tab extensively and it crashes kwin regularly since my last Ubuntu update using Discover.

The crash can be reproduced every time.

-- Backtrace:
Application: KWin (kwin_x11), signal: Aborted

[KCrash Handler]
#4  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:49
#5  0x00007f0e72646864 in __GI_abort () at abort.c:79
#6  0x00007f0e72aa5ba3 in QMessageLogger::fatal(char const*, ...) const () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#7  0x00007f0e7189eade in QSGRenderLoop::handleContextCreationFailure(QQuickWindow*, bool) () from /lib/x86_64-linux-gnu/libQt5Quick.so.5
#8  0x00007f0e718a098e in ?? () from /lib/x86_64-linux-gnu/libQt5Quick.so.5
#9  0x00007f0e718a177b in ?? () from /lib/x86_64-linux-gnu/libQt5Quick.so.5
#10 0x00007f0e7309f7c5 in QWindow::event(QEvent*) () from /lib/x86_64-linux-gnu/libQt5Gui.so.5
#11 0x00007f0e73778013 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Widgets.so.5
#12 0x00007f0e72cc21ca in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#13 0x00007f0e730949a1 in QGuiApplicationPrivate::processExposeEvent(QWindowSystemInterfacePrivate::ExposeEvent*) () from /lib/x86_64-linux-gnu/libQt5Gui.so.5
#14 0x00007f0e730692bb in QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Gui.so.5
#15 0x00007f0e6ca3f747 in ?? () from /lib/x86_64-linux-gnu/libQt5XcbQpa.so.5
#16 0x00007f0e72cc0a4b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#17 0x00007f0e72cc8fc6 in QCoreApplication::exec() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#18 0x000055c8f75d7a6d in ?? ()
#19 0x00007f0e72648cb2 in __libc_start_main (main=0x55c8f75d76a0, argc=3, argv=0x7ffc10b94458, init=<optimized out>, fini=<optimized out>, rtld_fini=<optimized out>, stack_end=0x7ffc10b94448) at ../csu/libc-start.c:314
#20 0x000055c8f75d7f8e in _start ()
[Inferior 1 (process 53045) detached]

Possible duplicates by query: bug 437761, bug 437693, bug 436607, bug 436528, bug 436520.

Reported using DrKonqi