gh-128277: use relaxed atomics for sock_fd

[kumaraditya303]

• Issue: Make socket module thread safe #128277

[asvetlov]

Looks good after the brief look

[colesbury]

I'm not sure it's worth doing these sorts of changes for file descriptors. We still have unfixable race conditions when sockets are closed concurrently (see #121544)

[colesbury]

The PR is fairly straightforward, so it's fine with me if you want to merge it. I just don't think we should bother with this sort of thing in the future.

[kumaraditya303]

I'm not sure it's worth doing these sorts of changes for file descriptors. We still have unfixable race conditions when sockets are closed concurrently (see #121544)

I see, I did this just for asyncio because tsan was complaining while running the existing test suite and this fixes all of this AFAICS. If we aren't planning to fix this maybe we should add some tsan suppressions for these for the time being?

[bedevere-bot]

⚠️⚠️⚠️ Buildbot failure ⚠️⚠️⚠️

Hi! The buildbot aarch64 Fedora Stable Clang 3.x has failed when building commit 7c72c1f.

What do you need to do:

1. Don't panic.
2. Check the buildbot page in the devguide if you don't know what the buildbots are or how they work.
3. Go to the page of the buildbot that failed (https://buildbot.python.org/#/builders/234/builds/6793) and take a look at the build logs.
4. Check if the failure is related to this commit (7c72c1f) or if it is a false positive.
5. If the failure is related to this commit, please, reflect that on the issue and make a new Pull Request with a fix.

You can take a look at the buildbot page here:

https://buildbot.python.org/#/builders/234/builds/6793

Failed tests:

• test.test_asyncio.test_events
• test_interpreters

Failed subtests:

• test_create_connection_local_addr_nomatch_family - test.test_asyncio.test_events.EPollEventLoopTests.test_create_connection_local_addr_nomatch_family

Summary of the results of the build (if available):

==

Click to see traceback logs

Traceback (most recent call last):
  File "/home/buildbot/buildarea/3.x.cstratak-fedora-stable-aarch64.clang/build/Lib/test/test_asyncio/test_events.py", line 715, in test_create_connection_local_addr_nomatch_family
    with self.assertRaises(OSError):
         ~~~~~~~~~~~~~~~~~^^^^^^^^^
AssertionError: OSError not raised


Traceback (most recent call last):
  File "/home/buildbot/buildarea/3.x.cstratak-fedora-stable-aarch64.clang/build/Lib/threading.py", line 1054, in _bootstrap_inner
    self.run()
    ~~~~~~~~^^
  File "/home/buildbot/buildarea/3.x.cstratak-fedora-stable-aarch64.clang/build/Lib/threading.py", line 996, in run
    self._target(*self._args, **self._kwargs)
    ~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/buildbot/buildarea/3.x.cstratak-fedora-stable-aarch64.clang/build/Lib/test/test_interpreters/test_stress.py", line 30, in task
    interp = interpreters.create()
  File "/home/buildbot/buildarea/3.x.cstratak-fedora-stable-aarch64.clang/build/Lib/test/support/interpreters/__init__.py", line 76, in create
    id = _interpreters.create(reqrefs=True)
interpreters.InterpreterError: interpreter creation failed
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