[Bug 1764853] Re: winbind returns PAM_AUTHINFO_UNAVAIL on first login after reboot

[msaxl]

Requested logs.
The failed first authentication is on Apr 21 11:05:28, immediatly after the second attempt succeeds.

Before I logged in with the domain account I checked that networking of the machine worked:
wbinfo -P and wbinfo -p both showed online, wbinfo -u displayed every user.

The DC is a Ubuntu 16.04 samba active directory. In a similar setup
where I have the same problem I use a "18.04" ubuntu samba dc, but lets
stay with this machine since I can reproduce the problem very reliably
and the machine reboots quickly.

/etc/nsswitch has the following setup:
passwd:         compat winbind systemd
group:          compat winbind systemd
shadow:         compat
gshadow:        files

hosts:          files resolve dns mdns_minimal
networks:       files

protocols:      db files
services:       db files
ethers:         db files
rpc:            db files

netgroup:       nis


** Attachment added: "logs.tar.xz"
   https://bugs.launchpad.net/ubuntu/+source/samba/+bug/1764853/+attachment/5124840/+files/logs.tar.xz

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https://bugs.launchpad.net/bugs/1764853

Title:
  winbind returns PAM_AUTHINFO_UNAVAIL on first login after reboot

Status in samba package in Ubuntu:
  Incomplete

Bug description:
  The following issue exists only on Ubuntu 18.04

  I've upgraded ubuntu from 17.10 and noticed that winbind does not work well.
  90% of the time I reboot my system I'm getting PAM_AUTHINFO_UNAVAIL when trying to log in with a domain account.
  clicking login again on the login screen most of the time succeeds (so the password is correct)

  I've checked if it works if I wait 10 minutes before logging in, no success, so it is not a timing issue.
  Also I've checked if winbind is working (log in with ssh using a local account)
  getent passwd xy and wbinfo -K user%pwd both work always.

  Now my workaround is putting
  winbind request timeout = 3
  in smb.conf, since the PAM_AUTHINFO_UNAVAIL is returned about 60sec after trying to login. This workaround solves nothing, it only makes logging in faster. (But now it fails mostly two times, but waiting 6 seconds is better than 60)

  To me it seems like deadlock, but I was unable to track it since it
  happens only on the first login. Then I would have to reboot
  (restarting winbind does not trigger it twice, also removing all
  caches in /run/samba does not trigger it twice)

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