Expected behaviour zombie processes

Expected behaviour zombie processes

[Oliver Schad]

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Hi everybody

I've observed the following situation:

root       490  0.0  0.0  13004  1596 ?        S    Nov05   0:00   s6-supervise lxe
root      2738  0.6  0.0      0     0 ?        Zsl  Nov05 251:13     [lxe] <defunct>

So you see a zombie process. What is the expected behaviour of
s6-supervise here? I would expect, that this case is solved immediatly
by s6-supervise and a new process is spawned.

The observed behaviour was, that no new process was spawned and even
s6-svc -r didn't respawn a process.

Best Regards
Oli

-- 
Automatic-Server AG •••••
Oliver Schad
Geschäftsführer
Turnerstrasse 2
9000 St. Gallen | Schweiz

www.automatic-server.com | oliver.schad@automatic-server.com
Tel: +41 71 511 31 11 | Mobile: +41 76 330 03 47

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Re: Expected behaviour zombie processes

[Laurent Bercot]

>Hi everybody
>
>I've observed the following situation:
>
>root       490  0.0  0.0  13004  1596 ?        S    Nov05   0:00   s6-supervise lxe
>root      2738  0.6  0.0      0     0 ?        Zsl  Nov05 251:13     [lxe] <defunct>
>
>So you see a zombie process. What is the expected behaviour of
>s6-supervise here? I would expect, that this case is solved immediatly
>by s6-supervise and a new process is spawned.
>
>The observed behaviour was, that no new process was spawned and even
>s6-svc -r didn't respawn a process.

  Hi Oli,
  There is no indication that the zombie lxe process is a direct child
of s6-supervise. What does 's6-svstat /run/service/lxe' say?

  If that lxe process was s6-supervise's child, s6-supervise should
definitely reap the zombie immediately and spawn a new lxe process;
failing to do so would be a bug that has, to my knowledge, never
happened. There is definitely something else at play here.

--
  Laurent