Version: (using KDE 4.1.0) Installed from: Ubuntu Packages PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 7980 root 39 19 19584 740 564 R 99 0.0 128:32.96 kdm
this isn't helpful at all. please attach gdb to the hanging process, interrupt it and create a backtrace. some strace output *might* be helpful, too.
KDM is unmaintained and not used in KDE Plasma 5. SDDM is the login manager used in KDE Plasma 5. If you still have this same issue with SDDM, please file an issue on the SDDM bugtracker (after doing a search for existing issues first!): https://github.com/sddm/sddm/issues/