So, I didn’t know about the call_module option of pam_unix2.so pam module. I spent one day trying to figure out why a pam stack would call pam_winbind without haveing “pam_winbind” in any file in /etc/pam.d and finally discovered that pam_unix2 was calling it because it was configured this way in /etc/security/pam_unix2.conf.
I learnt about pam_unix2 and I wish to know why anyone would use call_module instead of configuring PAM for calling the right module before pam_unix2.
Is there any advantage in letting pam_unix2 managing its own module stack instead of configuring pam files?

Thanks,
Giuseppe