Re: Killing a zombie process?

["Gary Duzan" <gary%duzan.org@localhost>]

In Message <Pine.NEB.4.64.1509241821230.1850%vps1.whooppee.com@localhost>,
   Paul Goyette <paul%vps1.whooppee.com@localhost>wrote:

=>I'm not sure how I got to this point (but see high-level steps below). 
=>I have this zombie process:
=>
=>root    27237  0.0  0.0       0      0 pts/2- Z          - 0:00.00 (sh)
=>
=>Various web resources say "kill the parent" and the zombie child will 
=>die, too.  But that's probably not a good idea here, since the parent is 
=>(or at least, appears to be) init (pid==1).

   Can you conform with "ps axl"?

=>I checked for other potential parents (ie, any process with pts/2 for 
=>its TTY), and found two shell processes (one was my "login" shell on 
=>that terminal, and the other was the result of a "su" command).  I 
=>logged out of both processes, but the zombie remained.
=>
=>This is the second time this has happened, and both times were when I 
=>was using pkgsrc's mksandbox to rebuild something.  The sandbox is 
=>"almost" standard, created with this command:
=>
=> 	# mksandbox	--src=/build/netbsd-local/src	\
=> 			--xsrc=/build/netbsd-local/xsrc	\
=> 			--rwdirs=/tmp			\
=> 		/sandbox
=>
=>(I added the rwdirs=/tmp so that /sandbox/tmp would be a memory-based 
=>tmpfs filesystem.)
=>
=>I wouldn't usually worry too much about the zombie, but it's running 
=>/bin/sh _from_within_the_sandbox_ and therefore its image/text file owns 
=>a reference to /sandbox/bin/sh and this reference prevents me from 
=>properly unmounting the sandbox.
=>
=>I suppose I could just manually run "umount -f" but I just hate forcing 
=>an unmount of an in-use file-system.  :)
=>
=>Suggestions?

   If init is really its parent, check its "ps axl" output and
check its WCHAN. If it isn't "wait", maybe run "ktruss -p 1" to
get an idea of what it is doing instead of wait*() calls.

				    Gary Duzan