Comment 10 for bug 1761737

> The smb.conf file for the 18.04 box shows it as being a standalone server, not a domain member. Is that expected? Are you managing its users locally via smbpasswd?

After uploading I noticed that too. No it is not intended. I changed it to

   security = ADS

again and added same settings as in 17.10. Unfortunately smbd is still crashing after accessing the share on 18.04.

> Was this 18.04 box a fresh install of samba 4.7.6, or did you at some point have 4.7.4 or earlier and upgrade?

I upgraded from 16.04 to the development release of 18.04 earlier this year. It is very possible that I had samba 4.7.4 at some point earlier this year.
I have another system with a fresh install of 18.04. smbd also crashes there.

> The moment I remove your "kerberos method" option (i.e., comment it), the crash no longer happens.

Hm, it still keeps crashing for me.
Now I changed smb.conf on 18.04 to this still crashing configuration:

[global]
        dns proxy = No
        domain master = No
        kerberos method = secrets and keytab
        local master = No
        log file = /var/log/samba/log.%m
        map to guest = Bad User
        max log size = 1000
        obey pam restrictions = Yes
        pam password change = Yes
        panic action = /usr/share/samba/panic-action %d
        passwd chat = *Enter\snew\s*\spassword:* %n\n *Retype\snew\s*\spassword:* %n\n *password\supdated\ssuccessfully* .
        passwd program = /usr/bin/passwd %u
        realm = MPI-DORTMUND.MPG.DE
        security = ADS
        server role = member server
        server string = %h %a
        syslog = 0
        unix password sync = Yes
        usershare allow guests = Yes
        workgroup = MPI-DORTMUND
        idmap config * : backend = tdb

> Can you elaborate on how this 18.04 machine is supposed to authenticate users and give them access or not to a share, since it's not part of the AD realm, at least according to smb.conf?

The 18.04 machine should prefer kerberos for authenticating users. Local authentication using sssd for AD is working fine. Kerberos authentication is working fine too.

There is a shared directory users should have access. It is working the other way round - on 17.10 with same settings:

[share]
        create mask = 0640
        directory mask = 0750
        force group = "Domain Users"
        invalid users = root
        path = /mnt/share
        read only = No
        valid users = +ntwsadmins "+Domain Users"