Issue #21315 has been updated by ko1 (Koichi Sasada). Status changed from Assigned to Closed Re-checked on master 4d185cce78 with a RUBY_DEBUG=1 build (RACTOR_CHECK_MODE > 0). Both halves of this ticket are fixed by the per-Ractor GC work (GH-18194), as I expected in #note-8. 1. The assertion in the description no longer fires: require "tempfile" Ractor.new { 10.times { Tempfile.new } }.join GC.start # master, RUBY_DEBUG=1: no assertion failure 2. jhawthorn's case in #note-1 -- a finalizer defined inside a Ractor running in the main Ractor and handing it an unshareable object -- is gone. That script now prints: ruby 4.0.2 : finalizing on #<Ractor:#1 running> (was: #<Ractor:#2 ...>) master : finalizing on #<Ractor:#2 running> (was: #<Ractor:#2 ...>) The finalizer runs in the Ractor that defined it, so the object it captured is never reachable from two Ractors at the same time. On the "what about terminated Ractors?" question from the thread: once a Ractor has terminated and its objspace has been absorbed by the joining Ractor, its outstanding finalizers run there. That is consistent, because at that point nothing else can reach those objects. ---------------------------------------- Bug #21315: Finalizers violate the `rb_ractor_confirm_belonging` assertion https://bugs.ruby-lang.org/issues/21315#change-118832 * Author: byroot (Jean Boussier) * Status: Closed * Assignee: ractor * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- Reproduction (with assertions enabled): ```ruby require "tempfile" Ractor.new do 10.times do Tempfile.new end end.take GC.start ``` ``` <OBJ_INFO:rb_ractor_confirm_belonging@../src/ractor_core.h:375> (File) /home/runner/work/ruby/ruby/src/lib/tempfile.rb:387: [BUG] rb_ractor_confirm_belonging object-ractor id:1, current-ractor id:2 ruby 3.5.0dev (2025-05-09T15:51:24Z pull/13291/merge e289a1dc58) +PRISM [x86_64-linux] -- Control frame information ----------------------------------------------- c:0005 p:0007 s:0025 e:000024 METHOD /home/runner/work/ruby/ruby/src/lib/tempfile.rb:387 [FINISH] c:0004 p:0022 s:0020 e:000019 METHOD /home/runner/work/ruby/ruby/src/lib/prism/parse_result.rb:833 [FINISH] c:0003 p:---- s:0012 e:000011 CFUNC :parse_lex_file c:0002 p:0006 s:0007 e:000006 BLOCK /home/runner/work/ruby/ruby/src/test/prism/ractor_test.rb:26 [FINISH] c:0001 p:---- s:0003 e:000002 DUMMY [FINISH] -- Ruby level backtrace information ---------------------------------------- /home/runner/work/ruby/ruby/src/test/prism/ractor_test.rb:26:in 'block in test_parse_lex_file' /home/runner/work/ruby/ruby/src/test/prism/ractor_test.rb:26:in 'parse_lex_file' /home/runner/work/ruby/ruby/src/lib/prism/parse_result.rb:833:in 'initialize' /home/runner/work/ruby/ruby/src/lib/tempfile.rb:387:in 'call' -- Threading information --------------------------------------------------- Total ractor count: 2 Ruby thread count for this ractor: 1 -- C level backtrace information ------------------------------------------- /home/runner/work/ruby/ruby/build/ruby(rb_print_backtrace+0x14) [0x561441aeedbf] ../src/vm_dump.c:843 /home/runner/work/ruby/ruby/build/ruby(rb_vm_bugreport) ../src/vm_dump.c:1175 /home/runner/work/ruby/ruby/build/ruby(bug_report_end+0x0) [0x561441aa3f39] ../src/error.c:1097 /home/runner/work/ruby/ruby/build/ruby(rb_bug_without_die_internal) ../src/error.c:1097 /home/runner/work/ruby/ruby/build/ruby(die+0x0) [0x5614416e237f] ../src/error.c:1115 /home/runner/work/ruby/ruby/build/ruby(rb_bug) ../src/error.c:1117 /home/runner/work/ruby/ruby/build/ruby(rb_ractor_confirm_belonging+0xde) [0x56144188c6be] ../src/ractor_core.h:376 /home/runner/work/ruby/ruby/build/ruby(vm_exec_core+0xef) [0x5614418b23ef] /home/runner/work/ruby/ruby/build/vm.inc:2500 /home/runner/work/ruby/ruby/build/ruby(rb_vm_exec+0x156) [0x5614418a4676] ../src/vm.c:2618 /home/runner/work/ruby/ruby/build/ruby(vm_call0_cc+0x13d) [0x5614418aa1dd] ../src/vm_eval.c:101 /home/runner/work/ruby/ruby/build/ruby(rb_vm_call0+0x4c) [0x5614418b1cc5] ../src/vm_eval.c:61 /home/runner/work/ruby/ruby/build/ruby(rb_vm_call_kw) ../src/vm_eval.c:326 /home/runner/work/ruby/ruby/build/ruby(rb_check_funcall_default_kw) ../src/vm_eval.c:694 /home/runner/work/ruby/ruby/build/ruby(rb_gc_run_obj_finalizer+0x1cf) [0x56144170220f] ../src/gc.c:306 /home/runner/work/ruby/ruby/build/ruby(rb_multi_ractor_p+0x0) [0x56144170246f] ../src/gc/default/default.c:2820 /home/runner/work/ruby/ruby/build/ruby(rb_vm_lock_enter) ../src/vm_sync.h:74 /home/runner/work/ruby/ruby/build/ruby(rb_gc_vm_lock) ../src/gc.c:137 /home/runner/work/ruby/ruby/build/ruby(finalize_list) ../src/gc/default/default.c:2843 /home/runner/work/ruby/ruby/build/ruby(finalize_deferred_heap_pages) ../src/gc/default/default.c:2866 ``` I think it wouldn't be hard to disable that check when running a finalizer, but I don't know if it's the correct thing to do. -- https://bugs.ruby-lang.org/