Bug #17516


forking in a ractor causes Ruby to crash

Added by pkmuldoon (Phil Muldoon) over 3 years ago. Updated 11 months ago.

Target version:
ruby -v:
ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [x86_64-darwin20]


I just want to point out, there's absolutely no reason to do this, but

r = do

Will cause:

internal:ractor:267: warning: Ractor is experimental, and the behavior may change in future versions of Ruby! Also there are many implementation issues.
[BUG] rb_thread_terminate_all: called by child thread (0x0000700004ddca40, 0x00007f981b567ee0)
ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [x86_64-darwin20]

-- Crash Report log information --------------------------------------------
See Crash Report log file under the one of following:
* ~/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 -----------------------------------------------
c:0001 p:---- s:0003 e:000002 (none) [FINISH]

-- C level backtrace information -------------------------------------------
=> #<Ractor:#3 (pry):5 terminated>
[4] pry(main)> /Users/phillipmuldoon/.rubies/ruby-3.0.0/bin/ruby(rb_vm_bugreport+0x6cf) [0x103084d1f]
/Users/phillipmuldoon/.rubies/ruby-3.0.0/bin/ruby(rb_bug_without_die+0x206) [0x102e9e2b6]
/Users/phillipmuldoon/.rubies/ruby-3.0.0/bin/ruby(rb_bug+0x71) [0x103091e6b]
/Users/phillipmuldoon/.rubies/ruby-3.0.0/bin/ruby(rb_thread_terminate_all+0x329) [0x10301e5b9]
/Users/phillipmuldoon/.rubies/ruby-3.0.0/bin/ruby(rb_ractor_terminate_all+0xa3) [0x102f8acc3]
/Users/phillipmuldoon/.rubies/ruby-3.0.0/bin/ruby(rb_ec_cleanup+0x229) [0x102ea9299]
/Users/phillipmuldoon/.rubies/ruby-3.0.0/bin/ruby(ruby_stop+0x9) [0x102ea9509]
/Users/phillipmuldoon/.rubies/ruby-3.0.0/bin/ruby(thread_start_func_2+0x8ce) [0x103027fce]
/Users/phillipmuldoon/.rubies/ruby-3.0.0/bin/ruby(thread_start_func_1+0x10d) [0x10302753d]
/usr/lib/system/libsystem_pthread.dylib(_pthread_start+0xe0) [0x7fff20382950]


ruby_2021-01-06-104315_phillip-muldoon-FA588.crash (31.8 KB) ruby_2021-01-06-104315_phillip-muldoon-FA588.crash crash report pkmuldoon (Phil Muldoon), 01/06/2021 11:12 AM

Updated by pkmuldoon (Phil Muldoon) over 3 years ago

ruby --version

ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [x86_64-darwin20]

Actions #3

Updated by pkmuldoon (Phil Muldoon) over 3 years ago

  • ruby -v set to ruby 3.0.0p0 (2020-12-25 revision 95aff21468) [x86_64-darwin20]

Updated by shyouhei (Shyouhei Urabe) over 3 years ago

This must be a bug.

Besides there is a technical difficulty to fork a multi-Ractor program (or, there is a technical difficulty to combine pthread and fork in general). I didn’t think we should allow such operation.

Further reading: this looong rationale written in

Updated by pkmuldoon (Phil Muldoon) over 3 years ago

I'm wondering if we can limit Process calls in the ractor as we do for accessing out of band variables? I've not had a chance to attach GDB to the Ruby VM yet (I have to compile Ruby with -O0 -g3 for things to be clear).

BTW I'm not suggesting anyone every do that code snippet in the original post! It's somewhat of a theoretical testcase. But the Ruby interpreter shouldn't crash either :thinking face:

Updated by hsbt (Hiroshi SHIBATA) over 2 years ago

  • Status changed from Open to Assigned
  • Assignee set to ko1 (Koichi Sasada)

Updated by jeremyevans0 (Jeremy Evans) 11 months ago

I submitted a pull request to disallow fork from inside a ractor:


Also available in: Atom PDF