smb.conf出现两个security = user 参数，费解？

弄了半天，然后在日志中看到：
PAM unable to dlopen(/lib/security/pam_userdb.so): /lib/security/pam_userdb.so: cannot open shared object file: No such file or directory

然后问google，得解决方案：
sudo ln -s /lib/i386-linux-gnu/security/pam_userdb.so /lib/security/pam_userdb.so