Skip channel program tests on Apple Silicon

[pcd1193182]

Motivation and Context

I have a small VM set up on my macbook to do some basic testing with. Unfortunately, the channel program tests consistently cause me problems. The issue appears to be that there is something wrong with our lua interpreter when running on apple silicon.

Description

This PR simply skips the channel program tests if it detects that it's running on Apple Silicon.

How Has This Been Tested?

Ran the test suite on my macbook and on a normal linux VM.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Performance enhancement (non-breaking change which improves efficiency)
• Code cleanup (non-breaking change which makes code smaller or more readable)
• Breaking change (fix or feature that would cause existing functionality to change)
• Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
• Documentation (a change to man pages or other documentation)

Checklist:

• My code follows the OpenZFS code style requirements.
• I have updated the documentation accordingly.
• I have read the contributing document.
• I have added tests to cover my changes.
• I have run the ZFS Test Suite with this change applied.
• All commit messages are properly formatted and contain Signed-off-by.

[robn]

Maybe I would make a is_linux_apple_silicon or similar to not have to repeat it. On the other hand, this is a temporary situation, so maybe making a proper function gives a suggestion of permanence that we don't want to encourage :)

[tonyhutter]

Thanks, you can squash these and should be good to go.

[adamdmoss]

I really rather believe, FWIW, that if there's "something wrong with our lua interpreter when running on apple silicon" then we should forbid channel program support on apple silicon, not forbid the tests, which seems counterproductive.

[tonyhutter]

@adamdmoss that's a good point. @pcd1193182 what are your thoughts on disabling all channel programs on Apple silicon until we get a real fix?

[robn]

You can't currently disable channel programs; snapshot destruction requires it (see dsl_destroy_snapshots_nvl()).

Regardless, this is a small, targeted test skip for a specific platform that keeps the rest of the test suite running on that platform and so keeps that platform working and useful for development. We do this all the time - we have Linux and FreeBSD skips throughout the test suite.

[tonyhutter]

@pcd1193182 can you give some more detail on the problem you're seeing? Is it a test-case problem, or a real problem with lua on Apple silicon?

[pcd1193182]

It's a real problem; if you try to run any lua program that triggers an exception (like the one in the divide by zero test), the setjmp/longjmp mechanism doesn't appear to work, and you end up with a panic on linux.