Comment 12 for bug 1822616

Fix proposed here: https://gitlab.gnome.org/3v1n0/mutter/merge_requests/1
That will at least make this particular crash impossible, and will close the bug.

P.S. An apparently unrelated problem which limits my ability to test the fix is that Xorg doesn't start properly with nvidia-drm.modeset=1 until after you have run it as root at least once. And if you do that then even this bug stops happening (no fix required). So there's something broken with basic Xorg when using nvidia-drm.modeset=1 and that might be the root cause here.