misc/54886: i386 testbed hangs running ATF tests

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

>Number:         54886
>Category:       misc
>Synopsis:       i386 testbed hangs running ATF tests
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    misc-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Jan 23 12:50:00 +0000 2020
>Originator:     Andreas Gustafsson
>Release:        NetBSD-current, source date >= 2020.01.16.16.47.19
>Organization:
>Environment:
System: NetBSD
Architecture: i386
Machine: i386
>Description:

On the TNF i386 testbed, the ATF tests runs are hanging since the
following commits:

  2020.01.16.16.47.19 martin src/usr.sbin/sysinst/bsddisklabel.c 1.35
  2020.01.16.16.47.19 martin src/usr.sbin/sysinst/defs.h 1.51
  2020.01.16.16.47.19 martin src/usr.sbin/sysinst/disks.c 1.60
  2020.01.16.16.47.19 martin src/usr.sbin/sysinst/main.c 1.20

The hang consistently occurs at the time of the
bin/sh/t_patterns:filename_expansion test case.

Since the above commits cause a tmpfs to be mounted at /tmp and the
tests are run in a qemu VM with 128 MB of RAM, 25% of which will
now be allocated to the tmpfs, I'm guessing this is related to
the tmpfs filling up or the system running low on available memory.

The pmax and hpcmips tests are also failing to complete since around
the same time.

The hang does not occur when running the tests on real hardware with
plenty of RAM.

For logs, see:

  http://releng.netbsd.org/b5reports/i386/commits-2020.01.html#2020.01.16.16.47.19

>How-To-Repeat:

>Fix: