misc/59252: tests/rump/rumpkern/t_sp:sigsafe: out of memory

[campbell+netbsd%mumble.net@localhost]

>Number:         59252
>Category:       misc
>Synopsis:       tests/rump/rumpkern/t_sp:sigsafe: out of memory
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    misc-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Apr 05 11:15:00 +0000 2025
>Originator:     Taylor R Campbell
>Release:        current
>Organization:
The rump t_sp Foundaleak
>Environment:
>Description:
The `sigsafe' test in tests/rump/rumpkern/t_sp has been intermittently failing for a long time.  I put in various diagnostic measures (e.g., PR bin/58112: daemonized rump conceals output on crash) to no avail, until I noticed this:

Pre-test stderr:
[1]   Killed                  ${Atf_Check} "${@}"
rump.halt: init failed: Connection refused
t_sp: ERROR: The test case cleanup returned a non-ok exit code, but this is not allowed

https://releng.netbsd.org/b5reports/i386/2025/2025.04.04.21.52.19/test.html#rump_rumpkern_t_sp_sigsafe

On review of the test logs, I see that a sampling of t_sp:sigsafe failures all show the uvm oom killer:

    sigsafe: [ 7629.0398811] UVM: pid 25563.25563 (h_sigcli), uid 0 killed: out of swap
[ 7629.0427354] UVM: pid 17924.17924 (sh), uid 0 killed: out of swap
[ 7629.0526265] UVM: pid 17976.26594 (rump_server), uid 0 killed: out of swap
[ 7629.0526265] UVM: pid 27133.27133 (atf-check), uid 0 killed: out of swap
[5.689429s] Failed: atf-check failed; see the output of the test for details

https://releng.netbsd.org/b5reports/i386/2025/2025.04.04.21.52.19/test.log

    sigsafe: [ 7541.7773590] UVM: pid 2566.14124 (rump_server), uid 0 killed: out of swap
[5.739012s] Failed: atf-check failed; see the output of the test for details

https://releng.netbsd.org/b5reports/i386/2025/2025.04.04.20.40.58/test.log

    sigsafe: [ 7636.1123173] UVM: pid 29410.16674 (rump_server), uid 0 killed: out of swap
[ 7636.1123173] UVM: pid 26178.26178 (sh), uid 0 killed: out of swap
[5.838166s] Failed: atf-check failed; see the output of the test for details

https://releng.netbsd.org/b5reports/i386/2025/2025.04.01.16.35.46/test.log
>How-To-Repeat:
On a low-memory machine:

atf-run /usr/tests/rump/rumpkern/t_sp:sigsafe | atf-report
>Fix:
Yes, please!