kern/46988: Zombies not exiting

[martin%NetBSD.org@localhost]

>Number:         46988
>Category:       kern
>Synopsis:       Zombies not exiting
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Sep 20 11:10:01 +0000 2012
>Originator:     Martin Husemann
>Release:        NetBSD 6.99.11
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD thirdstage.duskware.de 6.99.11 NetBSD 6.99.11 (MODULAR) #9: Thu 
Sep 20 11:12:29 CEST 2012 
martin%night-porter.duskware.de@localhost:/usr/src/sys/arch/sparc64/compile/MODULAR
 sparc64
Architecture: sparc64
Machine: sparc64
>Description:

Running the /usr/tests/lib/libc/sys t_pipe2 test sometimes ends with
a non-exiting zombie process:

12310 ?      Z    0:00.00 (t_pipe2)

This is a new effect, but not always reliably reproducable - race condition
in recent lwp exit changes?


>How-To-Repeat:

cd /usr/tests/lib/libc/sys && atf-run t_pipe2 | atf-report
and watch it hanging sometimes.

>Fix:
no idea