I'm also having this exact same problem.
Using Ubuntu 18.04.1 Desktop, kernel linux-image-4.15.0-45-generic.
Kernel linux-image-4.15.0-44-generic has the same problem.
I do not have any older kernel installed to test.
Login via ssh or via a terminal in the gnome gui works.
Login via Alt-Ctrl-Fx or when booted in runlevel 3 fails as described in the other posts.
I'm also having this exact same problem. 4.15.0- 45-generic. 4.15.0- 44-generic has the same problem.
Using Ubuntu 18.04.1 Desktop, kernel linux-image-
Kernel linux-image-
I do not have any older kernel installed to test.
Login via ssh or via a terminal in the gnome gui works.
Login via Alt-Ctrl-Fx or when booted in runlevel 3 fails as described in the other posts.