kern/54567: ATF tests time out after many failing quota tests

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

>Number:         54567
>Category:       kern
>Synopsis:       ATF tests time out after many failing quota tests
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Sep 24 18:45:00 +0000 2019
>Originator:     Andreas Gustafsson
>Release:        NetBSD-current, source date >= 2019.09.23.12.00.58
>Organization:

>Environment:
System: NetBSD
Architecture: i386
Machine: i386
>Description:

The last two i386 test runs and the last amd64 test run on the TNF
testbed have timed out.  Before the timeout, many file system quota
tests failed.  For example, in

  http://releng.netbsd.org/b5reports/amd64/2019/2019.09.22.23.34.13/test.log

there are failures like these:

  fs/ffs/t_getquota (677/846): 12 test cases
      get_be_1_both: [7.763016s] Failed: atf-check failed; see the output of the test for details
      get_be_1_group: [7.677171s] Failed: atf-check failed; see the output of the test for details
      get_be_1_user: [7.649336s] Failed: atf-check failed; see the output of the test for details
      get_be_2_both: [8.413508s] Failed: atf-check failed; see the output of the test for details
      get_be_2_group: [8.210313s] Failed: atf-check failed; see the output of the test for details
      get_be_2_user: [5.971845s] Failed: atf-check failed; see the output of the test for details
      get_le_1_both: [8.638174s] Failed: atf-check failed; see the output of the test for details
      get_le_1_group: [9.301078s] Failed: atf-check failed; see the output of the test for details
      get_le_1_user: [9.300100s] Failed: atf-check failed; see the output of the test for details
      get_le_2_both: [9.392300s] Failed: atf-check failed; see the output of the test for details
      get_le_2_group: [10.229272s] Failed: atf-check failed; see the output of the test for details
      get_le_2_user: [9.844319s] Failed: atf-check failed; see the output of the test for details
  [103.360256s]

followed by an "out of swap" error and a timeout.  The i386 testbed shows
similar failures (but without the "out of swap"):

  http://releng.netbsd.org/b5reports/i386/2019/2019.09.23.12.00.58/test.log

The build was broken for most of the time period when the problem
started, so it is unlikely to be easily bisectable.  And I can't test
it on real hardware because PR 54560.

>How-To-Repeat:

>Fix: