Re: Killing a zombie process?

[Paul Goyette <paul%vps1.whooppee.com@localhost>]

On Wed, 30 Sep 2015, Paul Goyette wrote:

> > # kill -HUP 1
> > # ps axl | grep ' Z '
> >   0 27237     1     0   0  0       0      0 -       Z    pts/2- 0:00.00 
> > (sh)
>
> Well, it happened again!
>
> I rebooted earlier today, and then deinstalled and rebuilt about 40
> packages within the pkgsrc/sysutils/mksandbox environment (all with
> MAKE_JOBS=3 enabled).  After all packages were rebuilt, I exit from
> the sandbox and run ./sandbox/dismount and get the error
>
> 	umount: /sandbox/bin: Device busy
>
> Sure enough, there's a new Zombie process, and its parent seems to be
> init  (PPID==0)
>
> 	# ps axl | grep ' Z '
> 	   0 23848 2812    0  85  0   4360    164 pipe_rd R+   pts/2  0:00.00 
> grep  Z
> 	   0 25439    1    0   0  0      0      0 -       Z    pts/2  0:00.00 
> (sh)
>
> HUPing init still doesn't help.
>
> So, I'm pretty sure that there's a bug somewhere, but haven't a clue
> on where  to start looking.

Interestingly, if I shutdown to single-user mode, the zombie process 
gets reaped and disappears!

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



+------------------+--------------------------+-------------------------+
| Paul Goyette     | PGP Key fingerprint:     | E-mail addresses:       |
| (Retired)        | FA29 0E3B 35AF E8AE 6651 | paul at whooppee.com    |
| Kernel Developer | 0786 F758 55DE 53BA 7731 | pgoyette at netbsd.org  |
+------------------+--------------------------+-------------------------+