Re: wait(2) and SIGCHLD

[christos%astron.com@localhost (Christos Zoulas)]

In article <28808.1597602399%jinx.noi.kre.to@localhost>,
Robert Elz  <kre%munnari.OZ.AU@localhost> wrote:
>    Date:        Sun, 16 Aug 2020 16:13:57 -0000 (UTC)
>    From:        christos%astron.com@localhost (Christos Zoulas)
>    Message-ID:  <rhbm04$57s$1%ciao.gmane.io@localhost>
>
>  | They don't vanish, they get reparented to init(8) which then wakes up
>  | and reaps them.
>
>That probably would work, approximately, but isn't what's supposed to
>happen when a child's parent is ignoring SIGCHLD - the child should
>skip zombie state, and simply be cleaned up.
>
>The difference would be detectable if init were sent a SIGSTOP
>(assuming that isn't one which would cause a system panic)
>so it would stop reaping children (temporarily) - processes of
>the type in question should not be showing up as zombies.

FreeBSD does what we do (reparent to init). Linux has autoreap
which moves the state of the process to DEAD without going through
ZOMBIE and adds it to the dead queue.

christos