AMD64 FreeBSD14/15 3.x multiprocessing test failures

[picnixz]

Bug report

Bug description:

I don't know which one is the faulty commit so I'm tagaging everyone involved in the recent failures of this build bot.

The build bot is failing since 0c356c8 (cc @skirpichev) but there were warnings since 954b2cf (cc @bswck @sobolevn) for the same tests (I doubt Sergey's commit is actually the faulty one as it shouldn't have touched the interpreter's code itself)

Before that, similar failures appeared since c66ffcf (cc @Yhg1s) and before then, it was failing for a different reason but it was fixed in 102f825.

CPython versions tested on:

CPython main branch

Operating systems tested on:

No response

Linked PRs

• gh-132719: Fix AMD64 FreeBSD14/15 3.x failures - test_rlock_locked_2processes used an unknown Value #132774
• gh-132719: Skip multiprocessing test if missing ctypes #132842
• gh-132719: Skip multiprocessing test if missing ctypes #132846

[skirpichev]

I would guess it's 954b2cf.

"Warning" actually was a failure for the same test (test_many_threads_running_interp_in_other_interp) in one case. Perhaps, now it's flacky with a low chance to be successful on a re-run.

[chris-eibl]

I think it is 15c75d7.

AMD64 FreeBSD15 3.x is failing since this commit with

    test.test_multiprocessing_fork.test_processes
    test.test_multiprocessing_forkserver.test_processes
    test.test_multiprocessing_spawn.test_processes

In this case, 15c75d7 was the only change: https://buildbot.python.org/#/builders/1238/builds/5328.

https://buildbot.python.org/#/builders/1232/builds/5365 on AMD64 FreeBSD14 3.x shows the known test.test_interpreters.test_stress.StressTests.test_many_threads_running_interp_in_other_interp failure (#127108).
This one has the commits 0c356c8 and 0c356c8, but I think they aren't the culprit.

However, beginning with https://buildbot.python.org/#/builders/1232/builds/5366 the AMD64 FreeBSD14 3.x bot also starts failing with

    test.test_multiprocessing_fork.test_processes
    test.test_multiprocessing_forkserver.test_processes
    test.test_multiprocessing_spawn.test_processes

and 15c75d7 is part of the three changes in there, too.

[YvesDup]

I will send a fix today

[gpshead]

thanks! your fix made sense, merged. reopen if something strange happens and it doesn't.