[systemd-devel] Missing kernel service for systemd causes user at 0.service to fail

[tedheadster]

Team,
  I have compiled my linux kernel using 'allnoconfig' and added back
in all the kernel options that have been documented as necessary for
systemd. I'm still getting an error. It fails trying to start
user at 0.service, and it is related to PAM somehow.

Here is the debug log:

Feb 14 23:48:57 intel486 systemd[1]: user at 0.service: About to execute:
/lib/systemd/systemd --user
Feb 14 23:48:57 intel486 systemd[1]: user at 0.service: Forked
/lib/systemd/systemd as 111
Feb 14 23:48:57 intel486 systemd[1]: user at 0.service: Changed dead -> start
Feb 14 23:48:57 intel486 systemd[1]: Starting User Manager for UID 0...
Feb 14 23:48:57 intel486 systemd[1]: user at 0.service: User lookup
succeeded: uid=0 gid=0
Feb 14 23:48:57 intel486 systemd[111]: user at 0.service: Kernel keyring
not supported, ignoring.
Feb 14 23:48:57 intel486 systemd[111]: PAM failed: Function not implemented
Feb 14 23:48:57 intel486 systemd[111]: user at 0.service: Failed to set
up PAM session: Function not implemented
Feb 14 23:48:57 intel486 systemd[111]: user at 0.service: Failed at step
PAM spawning /lib/systemd/systemd: Function not implemented
Feb 14 23:48:59 intel486 systemd[1]: Received SIGCHLD from PID 111 ((systemd)).
Feb 14 23:48:59 intel486 systemd[1]: Child 111 ((systemd)) died
(code=exited, status=224/PAM)
Feb 14 23:48:59 intel486 systemd[1]: user at 0.service: Child 111 belongs
to user at 0.service
Feb 14 23:48:59 intel486 systemd[1]: user at 0.service: Main process
exited, code=exited, status=224/PAM
Feb 14 23:49:00 intel486 systemd[1]: user at 0.service: Failed with
result 'protocol'.
Feb 14 23:49:00 intel486 systemd[1]: user at 0.service: Changed start -> failed
Feb 14 23:49:00 intel486 systemd[1]: user at 0.service: Job
user at 0.service/start finished, result=failed
Feb 14 23:49:00 intel486 systemd[1]: Failed to start User Manager for UID 0.

Trying to run this post-boot under strace did not get me any good leads.

What do you suggest to track this kernel configuration option down?

- Matthew