gh-117657: Log TSAN warnings to separate files and archive them

[mpage]

This ensures we don't lose races that occur in subprocesses or interleave races from workers running in parallel.

Log files are collected and packaged into a zipfile than can be downloaded from the "Artifacts" section of the workflow run (example).

The handle_segv=0 change to the TSAN options is necessary to avoid logs like this in default builds. I don't know what's causing this, but our ASAN builds also set the option.

The additional thread leak suppression was also required.

• Issue: Make TSAN tests pass with the GIL disabled in free-threaded builds #117657

[colesbury]

Should we cat the TSAN logs so that they are visible directly from the GitHub actions page?

[hugovk]

The example at https://github.com/mpage/cpython/actions/runs/8993391354 is a 170 KB zip containing 33 files, so it might not be practical to cat them all.

[mpage]

The example at https://github.com/mpage/cpython/actions/runs/8993391354 is a 170 KB zip containing 33 files, so it might not be practical to cat them all.

I don't feel super strongly either way.

On the one hand, that doesn't seem that bad? It's also with ~all the suppressions removed, so it's roughly the worst case scenario. In the common case (i.e. a new race appears), I would imagine it would be a lot less output.

On the other hand, downloading a zip file to look at the reported races doesn't feel particularly onerous.

[colesbury]

LGTM

I might just be lazy, but having the logs available in the GitHub UI seems nice to have. We currently print the logs and I wouldn't expect them to be significantly longer with this change. If we are concerned about super long logs, we could also just head -n 1000 or some other reasonably large length.

[mpage]

@hugovk@colesbury - The most recent version of this should be a happy medium and includes a few changes:

1. We always show the first 1000 lines of each log.
2. The "Archive TSAN logs" step no longer shows a warning if no files are found.

You can look at this workflow run as an example of what things look like on both success and failure. I removed suppressions from the free-threaded build so the TSAN job fails.

[colesbury]

Great!

We probably want to backport this to 3.13, right?

[mpage]

We probably want to backport this to 3.13, right?

Yeah, I think that's worth doing.

[miss-islington-app]

Thanks @mpage for the PR, and @colesbury for merging it 🌮🎉.. I'm working now to backport this PR to: 3.13.
🐍🍒⛏🤖

[bedevere-app]

GH-118931 is a backport of this pull request to the 3.13 branch.