Comment 19 for bug 239069

Looks like I've run into this bug as well. Ubuntu server 10.04, 64 bit (installed from an iso image downloaded 27/01/2012 from ubuntu.com).

I logged in to my box using my admin account and then ran 'sudo su' to change to root. To create the [new user] account I:
1. Created linux user [new user] ('useradd [new user]').
2. Created samba user [new user] ('smbpasswd -a [new user]').
3. Wanted to test the account so I 'su [new user]' then 'exit' back to my admin/root shell.
4. I realised I'd mis-type the [new user] username so deleted samba account ('smbpasswd -x [new user]') and tried to delete the linux account 'userdel [new user]'. Got error 'userdel: user [new user] is currently logged in'. I exited the terminal ssh session and logged back in but got same error.

'ps -U [new user] -a' gives me:

  PID TTY TIME CMD
 2837 pts/0 00:00:00 su
 2838 pts/0 00:00:00 bash
 2860 pts/0 00:00:00 ps

If I kill these processes, my admin/root session ends and when I log back in I get the same 'userdel: user [new user] is currently logged in' error. Running 'who' doesn't show [new user] logged in, just the admin account I'm logged in as.