On CentOS7.4, after upgrading to main line kernel 4.14.14-1.el7.elrepo.x86_64, the system hangs and does not enter the GUI after GNOME display manager was succesfully loaded. I made sure the new initrams was loaded and backed up and had run dracut -f
Did you see any warning information in dmesg? Might be better to raise this to CentOS forum first IMO :)