[systemd-devel] pam_systemd.so and su

[Mike Kazantsev]

On Sun, 18 Mar 2012 18:26:53 -0600
Canek Peláez Valdés <caneko at gmail.com> wrote:

> On Sun, Mar 18, 2012 at 5:43 PM, Kok, Auke-jan H
> <auke-jan.h.kok at intel.com> wrote:
> > On Sun, Mar 18, 2012 at 3:08 PM, Canek Peláez Valdés <caneko at gmail.com> wrote:
> >> 
> >> When I use su to become root, after logout the following message appears:
> >>
> >> ...killed.
> >>

I can't recall ever facing that "message", so maybe you can explain
what does it mean?
Are the long-running processes you've started from "su" get killed?
...along with su itself, which produces that message?

Also, maybe that is similar to the past logind issue?
http://thread.gmane.org/gmane.comp.sysutils.systemd.devel/4370/


> >> So, two questions:
> >>
> >> 1. Why is my session being killed at logout time?
> >>
> >> 2. The pam_systemd.so is really necessary? The "...killed." message
> >> appears after two or three seconds, and it's slightly annoying.
> >
> > please read `man pam_systemd`...
> 
> OK, done. Still doesn't understand. The kill-session-processes option
> is not set, so it should default to "no", right? Also, my
> /etc/systemd/systemd-logind.conf has no options set, in particular
> KillOnlyUsers is not set, and therefore is should default to "no",
> right? So, again, if both options are no, what is killing my session
> at logout time?
> 

I can suggest to check what exactly kills the processes by connecting
strace to:

  a) systemd itself ("strace -s65535 -f -p 1 2>&1 | grep kill")
  b) systemd-logind
  c) su process (*after* it was started)

I'm suggesting this because systemd can kill leftover pids when
cleaning up controller hierarchies, logind can kill the session,
pam_systemd seem to have a kill-parameter and probably can do it by
itself as well.

When debugging somewhat similar issue in the past, I've wasted a lot of
time mistakingly assuming that it's either logind or pam_systemd that
does the killing, while in fact it was totally unrelated to
kill-switches in both of them (more details can be found here:
http://goo.gl/S5ZLO).


-- 
Mike Kazantsev // fraggod.net
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