kern/54377: lib/libc/sys/t_ptrace_wait4/resume1 test case fails randomly

[gson%gson.org@localhost (Andreas Gustafsson)]

>Number:         54377
>Category:       kern
>Synopsis:       lib/libc/sys/t_ptrace_wait4/resume1 test case fails randomly
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Jul 16 07:35:00 +0000 2019
>Originator:     Andreas Gustafsson
>Release:        NetBSD-current, source date 2019.07.13.09.47.14
>Organization:

>Environment:
System: NetBSD
Architecture: x86_64
Machine: amd64
>Description:

The resume1 test case of the lib/libc/sys/t_ptrace_wait4 test program
fails randomly, even on real hardware.

>How-To-Repeat:

  cd /usr/tests/lib/libc/sys
  while ./t_ptrace_wait4 resume1 >/tmp/stdout 2>/tmp/stderr; do echo -n .; done

On my system, this either hangs or exits with a nonzero exit status within
a few seconds.

>Fix: