ruby-head builds have been failing since 2026-08-07

[tikkss]

Ensure the following before filing this issue

• I verified it reproduces with the latest version with - uses: ruby/setup-ruby@v1 (see Versioning policy)

• I tried to reproduce the issue locally by following the workflow steps (including all commands done by ruby/setup-ruby, except for Downloading Ruby & Extracting Ruby),
  and it did not reproduce locally (if it does reproduce locally, it's not a ruby/setup-ruby issue)

Are you running on a GitHub-hosted runner or a self-hosted runner?

GitHub-hosted runner

Link to the failed workflow job (must be a public workflow job, so the necessary information is available)

https://github.com/ruby/ruby-dev-builder/actions/runs/32592837360/job/97079257443#step:22:984

Any other notes?

The daily "CRuby Dev Builds" workflow in ruby/ruby-dev-builder has failed every day since 2026-08-07:

• https://github.com/ruby/ruby-dev-builder/actions/workflows/build.yml

Because of this, ruby-version: head currently installs a snapshot from 2026-08-05:

• https://github.com/ruby/ruby-dev-builder/releases

Only the build (ubuntu-26.04-arm, head) job fails, during make test-all TESTS="-j4". All other platforms build and test successfully, but since one matrix job fails, the "Publish Release" step is skipped and no new release is published.

This looks like a ruby master issue on aarch64-linux rather than a issue in ruby-dev-builder. For what it is worth, it does not seem to reproduce on the rubyci.org Ubuntu 26.04 aarch64 machines, which have been green for the same period:

• https://logs.rubyci.org/ubuntu-arm/ruby-master/recent.html