[systemd-devel] systemd "hangs" for several minutes on shutdown if it gets "service force-reload" request

[Andrey Borzenkov]

On Fri, Jan 7, 2011 at 5:33 AM, Lennart Poettering
<lennart at poettering.net> wrote:
> On Wed, 01.12.10 22:55, Andrey Borzenkov (arvidjaar at gmail.com) wrote:
>
>> In Mandriva we are using {ifup,ifdown}.d script for callouts. One
>> package install script that - in both cases - does "service vnstat
>> force-reload". During shutdown it is causing interesting effect - this
>> request hangs which causing network service (that indirectly calls it)
>> to hang as well and be finally killed:
>
> [...]
>
>> What I wonder in this case, why vnstat.service/reload appears to hang
>> in this case? The job itself fails during startup (initscript is
>> disabled, so it gets indirect request from ifup and does nothing):
>
> Does this probelm still exist?
>

Well, I just had shutdown stuck for 3 minutes using v17. It is hard to
tell whether this is the same case - either systemd does not report
timeout without log_level-debug or it scrolls up too fast to notice.

The question still remains - why systemd hangs in this case?

> Most likely this is simply an ordering deadlock: systemd executes
> something that asks systemd to execute something else which however is
> order after the first unit.

vnstat itself does not have any explicit dependencies. So in this case
this were caused by implicit dependencies added by systemd ....

 That is is not really fixable. At least I am
> have no idea what we could do about this.
>
> Lennart
>
> --
> Lennart Poettering - Red Hat, Inc.
>