Re: Killing a zombie process?

[Robert Elz <kre%munnari.OZ.AU@localhost>]

    Date:        Wed, 30 Sep 2015 15:55:04 +0800 (PHT)
    From:        Paul Goyette <paul%vps1.whooppee.com@localhost>
    Message-ID:  <Pine.NEB.4.64.1509301551450.12641%vps1.whooppee.com@localhost>

  | So there must be some difference in how init(8) waits during normal 
  | operation and how it waits during the transition to single-user.

Either that (which isn't really all that likely I'd guess) or perhaps
the process is not yet linked to init, so can't be waited upon.   It
needs to be on init's child queue for wait to find it, regardless of
what the ppid has been set to.

I think I'd be checking out the sequence in the sys_exit() code, to see if
there's anything that happens, or could happen, between setting the ppid to 1
and linking the process onto process 1's child list that could perhaps block
and cause the zombie to just sit there (for this, once the process status
is Z, you can't really trust some of the other ps output, pid and ppid
should be correct, but whan is unlikely to have any meaning).

kre