Bug #21200: Ractor spuriously hangs, segfaults or errors on TestEtc#test_ractor_parallel

• Status: Open
• Assignee: ractor
• Target version: -
• Backport: 3.1: UNKNOWN, 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN

[Eregon (Benoit Daloze)]

For a new test test_ractor_parallel I added in https://github.com/ruby/etc/pull/52/files

This seems a Ractor bug.

Example failures:
https://github.com/ruby/ruby/actions/runs/14097239052/job/39486770259?pr=12990

    1) Failure:
  TestEtc#test_ractor_parallel [/Users/runner/work/ruby/ruby/src/test/etc/test_etc.rb:178]:
  assert_separately failed with error message
  pid 51588 exit 0
  | [BUG] 

https://github.com/ruby/ruby/actions/runs/14094646363/job/39479353266?pr=12984#step:14:814

  TestEtc#test_ractor_parallel [/Users/runner/work/ruby/ruby/src/test/etc/test_etc.rb:178]:
  assert_separately failed with error message
  pid 47346 exit 0
  | [BUG] pthread_mutex_lock: Invalid argument (EINVAL)
  | ruby 3.5.0dev (2025-03-26T22:25:25Z pull/12984/merge 1ea32181b7) +PRISM [arm64-darwin23]
  | 
  | -- Crash Report log information --------------------------------------------
  |    See Crash Report log file in one of the following locations:
  |      * ~/Library/Logs/DiagnosticReports
  |      * /Library/Logs/DiagnosticReports
  |    for more details.
  | Don't forget to include the above Crash Report log file in bug reports.
  | 
  | -- Control frame information -----------------------------------------------
  | 
  | 
  | -- Threading information ---------------------------------------------------
  | Total ractor count: 1
  | Ruby thread count for this ractor: 0
  | 
  | -- C level backtrace information -------------------------------------------
  | [BUG] Segmentation fault at 0xfffffffffffffff8
  | ruby 3.5.0dev (2025-03-26T22:25:25Z pull/12984/merge 1ea32181b7) +PRISM [arm64-darwin23]
  | 
  | -- Crash Report log information --------------------------------------------
  |    See Crash Report log file in one of the following locations:
  |      * ~/Library/Logs/DiagnosticReports
  |      * /Library/Logs/DiagnosticReports
  |    for more details.
  | Don't forget to include the above Crash Report log file in bug reports.
  | 
  | Crashed while printing bug report
  | [IMPORTANT]
  | Don't forget to include the Crash Report log file under
  | DiagnosticReports directory in bug reports.
  |

https://github.com/ruby/ruby/actions/runs/14069270994/job/39402894235#step:12:951

    1) Error:
  TestEtc#test_ractor_parallel:
  Test::Unit::ProxyError: execution of Test::Unit::CoreAssertions#assert_separately expired timeout (10 sec)
  pid 145797 killed by SIGKILL (signal 9)
  | 
  
      /home/runner/work/ruby/ruby/src/test/etc/test_etc.rb:178:in 'TestEtc#test_ractor_parallel'

The test has been disabled for now in https://github.com/ruby/ruby/pull/12992.

[Eregon (Benoit Daloze)]

• Subject changed from Ractor spuriously hangs, segfault or errors to Ractor spuriously hangs, segfaults or errors on TestEtc#test_ractor_parallel