FileIO Strace test fails on Gentoo (test_fileio test_syscalls_read)

[cmaloney]

Bug report

Bug description:

Initially reported in PR comments: #123413

There looks like three cases to investigate/work on from this:

1. Gentoo + musl -> there is an extra mmap call
2. Gentoo + sandbox -> many additional calls (Probably an environment to disable in if can detect)
3. Should there be a more general switch to disable?

relates to: gh-120754

My first thought for 1 is mmap could generally be filtered out (it has shown up moderately frequently in my testing on other systems, generally used for memory allocation in wrapping). Working on setting up a Gentoo environment to test / experiment / investigate locally and develop patches.

cc: @mgorny, @vstinner, @gpshead, @hauntsaninja

CPython versions tested on:

CPython main branch

Operating systems tested on:

Linux

Linked PRs

• gh-127076: Disable strace tests under LD_PRELOAD #127086
• gh-127076: Ignore memory mmap in FileIO testing #127088

[cmaloney]

@mgorny good to close / Gentoo build working with latest main (and hopefully that will mean with next alpha as well)?

[mgorny]

Yes, looks like these tests now pass on musl, and are skipped in sandbox. Thanks a lot!