kern/55570: tests/modules/t_threadpool broken

[martin%NetBSD.org@localhost]

>Number:         55570
>Category:       kern
>Synopsis:       tests/modules/t_threadpool broken
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Aug 14 05:35:00 +0000 2020
>Originator:     Martin Husemann
>Release:        NetBSD 9.99.70
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD thirdstage.duskware.de 9.99.70 NetBSD 9.99.70 (MODULAR) #364: Thu Aug 13 14:45:04 CEST 2020 martin%thirdstage.duskware.de@localhost:/usr/src/sys/arch/sparc64/compile/MODULAR sparc64
Architecture: sparc64
Machine: sparc64
>Description:

The threadpool tests are broken by design and randomly fail in -current
(due to overall bad state of -current, scheduler issues and locking bugs
preventing various rump_server processes from shutting down gracefully).

The tests load a module and expect it to be available after 1s:
# The kernel test jig includes a 1 second delay in the job.  We need to
# wait longer for it to complete.
job_delay=2


This plain fails most of the time in current when not running this test in
isolation, but as part of the full ATF test suite. The 2 second delay also
is not portable enough for slow machines.

>How-To-Repeat:

see it works:
	cd /usr/tests/modules && atf-run t_threadpool

see it most often fails:
	cd /usr/tests && atf-run

>Fix:
Maybe the test should include a proper handshake to verify the module
has completed its job?