I'm running Oracle Linux on VirtualBox, using Gnome desktop environment. After I installed the guest tools to use shared folder (and some kernel/headers related packages mandated by the installer), graphical desktop stopped working.When I try to log in, only black screen appears with the cursor, and after a minute I'm taken back to login screen. After a research I got impression something didn't install cleanly, and Gnome got broken.How do I fix this? I thought about uninstalling those tools in text mode (CTRL + alt + F2), but for some reason this terminal doesn't haven even yum installed. And the thing is, I don't remember the name of those kernel/header packages I installed before the guest tool. I'm not even sure if that is cause of the problem. 
Oracle Linux server, black screen after login, and back to login screen
linux;gnome;virtualbox;oracle linux;oracle