Bug #21670: 3.4.5 crashing with "try to mark T_NONE object"

• Status: Open
• Assignee: -
• Target version: -
• ruby -v: ruby 3.4.5 (2025-07-16 revision 20cda200d3) +PRISM [x86_64-linux]
• Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN

[esaron (Es Aron)]

We're experiencing a large number of crashes while running tests in CI on Ubuntu 22.04 runners. It is inconsistent, and we cannot reproduce reliably, although when the crash happens it appears to always happen in the same place, even if during different tests.

This occurs both with and without YJIT enabled.

[byroot (Jean Boussier)]

It's in mark_method_entry_i, which rings a bell. @jhawthorn (John Hawthorn) didn't you fix that one?

@esaron please try the latest patch release: 3.4.7, your issue looks a lot like a missing write barrier issue and John fixed many of them in 3.4.7: https://github.com/ruby/ruby/compare/v3_4_5...v3_4_7