Patch libunwind manually to fix the access violation to unblock source build

[cshung]

This is meant to port libunwind/libunwind#717 directly from libunwind to unblock source build.

It is meant to be temporarily, once we have the libunwind updated we will revert this an take a proper update from there.

See the conversation here for the context.

@am11, @EgorBo

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Issue Details

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This is meant to port libunwind/libunwind#717 directly from libunwind to unblock source build.

It is meant to be temporarily, once we have the libunwind updated we will revert this an take a proper update from there.

@am11, @EgorBo

Author:	cshung
Assignees:	cshung
Labels:	area-Diagnostics-coreclr, needs-area-label
Milestone:	-

[janvorli]

@cshung is the issue that this fixes really blocking the source build? I believe this blocks debuggers only as it is remote unwind specific. I have thought that the issue that was blocking the source build was the race that I've found yesterday.

[cshung]

@cshung is the issue that this fixes really blocking the source build? I believe this blocks debuggers only as it is remote unwind specific. I have thought that the issue that was blocking the source build was the race that I've found yesterday.

I don't actually know exactly what happened there, I attached the link to the conversation leading to this PR above. Note that it also unblocks collecting dump on CI.

[am11]

Please add a line Apply https://github.com/libunwind/libunwind/pull/714 in https://github.com/dotnet/runtime/blob/main/src/native/external/libunwind-version.txt so we can keep track of delta.

[am11]

Looks great, thank you! :)

For the future, maybe we can add a few tests to catch these issues earlier, if possible? (as a separate PR)

[janvorli]

My patch PR for the other issue is here:
#97817

[janvorli]

LGTM, thank you!

[cshung]

Looks great, thank you! :)

For the future, maybe we can add a few tests to catch these issues earlier, if possible? (as a separate PR)

We chatted about it, since this is a regression in libunwind, it makes sense to have the test there so that we catch it upstream.

We were invited to write a unit test for it here. It would be great if you can help.

[am11]

We were invited to write a unit test for it here. It would be great if you can help.

I meant if we could create a test in runtime repo, that would be useful. We are updating libunwind once a year, failing one build leg like the CG2 error message in source-build CI would be enough to catch it earlier on.

I’m actually interested in writing an integration test in libunwind, which will run periodically and test build runtime (docker container in GitHub Actions pipeline), so we don’t have to troubleshoot one year worth of issues after the release. Will draft a proposal to libunwind maintainers over this weekend or so.