WORKAROUND:
Before trying to log in, do this:
1. Ctrl+Alt+F4, log in to VT4 and run: sudo Xorg :4 vt4
2. Ctrl+Alt+F1, wait for the log screen to reappear, then log in normally. No crash.
Something about having run Xorg as root already seems to be enough to avoid the bug in the Nvidia driver which is the root cause here.
WORKAROUND:
Before trying to log in, do this:
1. Ctrl+Alt+F4, log in to VT4 and run: sudo Xorg :4 vt4
2. Ctrl+Alt+F1, wait for the log screen to reappear, then log in normally. No crash.
Something about having run Xorg as root already seems to be enough to avoid the bug in the Nvidia driver which is the root cause here.