Profiler broken on ruby-head (after preview2) with "RuntimeError pthread_id_for() self-test failed"

[ivoanjo]

Current behaviour

The profiler is broken on latest ruby-head:

$ ruby -v
ruby 3.3.0dev (2023-10-20T07:33:23Z master 0061eaddc9) [x86_64-linux]

Failing with this issue:

W, [2023-10-20T10:43:58.474250 #74964] WARN -- ddtrace: [ddtrace] Profiling was requested but is not supported, profiling disabled: There was an error loading the profiling native extension due to 'RuntimeError pthread_id_for() self-test failed' at 'dd-trace-rb/lib/datadog/profiling.rb:111:in `native_working?''

This failure happens at run-time (when trying to enable the profiler) so it does not impact the application in any way, other than not having profiling.

Thus:

• The app will continue to work fine
• Other features of dd-trace-rb (tracing, asm, ...) will continue to work fine

Expected behaviour

Profiling should be working.

Steps to reproduce

Install dd-trace-rb and try to profile an app running on Ruby 3.3.

Environment

• ddtrace version: master
• Configuration block (Datadog.configure ...): N/A
• Ruby version: ruby 3.3.0dev (2023-10-20T07:33:23Z master 0061eaddc9) [x86_64-linux]
• Operating system: Ubuntu 22.04.3 LTS
• Relevant library versions: N/A

[ivoanjo]

Good news! It looks like this issue is fixed by refreshing the Ruby VM headers from debase-ruby_core_source. So once they pick up the next Ruby release (probably -preview3 or -rc1), we'll be able to upgrade and should be able to run fine again on 3.3.

[ivoanjo]

This is fixed by #3284. For profiling Ruby 3.3.0, we recommend using the latest dd-trace-rb, which as of this writing is v1.19.0 :)