Comment 11 for bug 829221

In source3/passdb/pdb_interface.c, pdb_get_methods_reload() assumes that pdb->free_private_data will always be set and callable. This is not the case for the tdbsam backend, which has:

        /* no private data */

        (*pdb_method)->private_data = NULL;
        (*pdb_method)->free_private_data = NULL;

(source3/passdb/pdb_tdb.c)

and pam_smbpass does call initialize_password_db(True, NULL), which triggers this codepath.

The only thing that's not clear to me is why people haven't been reporting this issue in droves before now. Tamer, have you configured pam_smbpass to be used for account authorization in addition to authentication? Can you attach /etc/pam.d/common-* and /etc/pam.d/lightdm?