Issue #21664 has been reported by Eregon (Benoit Daloze). ---------------------------------------- Bug #21664: Segfault when running Ractor tests in the same process https://bugs.ruby-lang.org/issues/21664 * Author: Eregon (Benoit Daloze) * Status: Open * Assignee: ractor * ruby -v: ruby 3.5.0dev (2025-11-01T19:14:42Z master 48c7f349f6) +PRISM [x86_64-linux] * Backport: 3.2: UNKNOWN, 3.3: UNKNOWN, 3.4: UNKNOWN ---------------------------------------- When running the tests from https://github.com/ruby/ruby/blob/master/bootstraptest/test_ractor.rb in a single process, I see segfaults occurring every time on the following tests: ``` # move object with generic ivar # move object with many generic ivars # move object with complex generic ivars # moved composite types move their non-shareable parts properly ``` To run those tests in the same process, I wrote a simple harness in https://github.com/eregon/ractor-shim/blob/main/test/run_tests.rb Full reproduction steps: ``` git clone --branch ruby3.5-segfault-repro git@github.com:eregon/ractor-shim.git cd ractor-shim ruby test/run_tests.rb ``` Result: ``` Running test from line 1941: <internal:ractor>:743: [BUG] Object is missing entry in generic_fields_tbl ruby 3.5.0dev (2025-11-01T19:14:42Z master 48c7f349f6) +PRISM [x86_64-linux] -- Control frame information ----------------------------------------------- c:0012 p:0003 s:0076 e:000075 l:y n:0001 METHOD <internal:ractor>:743 c:0011 p:0008 s:0069 e:000068 l:y n:0001 METHOD <internal:ractor>:330 c:0010 p:0045 s:0062 E:000648 l:n n:---- EVAL /home/eregon/code/ractor-shim/test/test_ractor.rb:1946 [FINISH] c:0009 p:---- s:0056 e:000055 l:y n:---- CFUNC :eval c:0008 p:0014 s:0048 e:000047 l:n n:---- BLOCK test/run_tests.rb:128 [FINISH] c:0007 p:---- s:0045 e:000044 l:y n:---- CFUNC :catch c:0006 p:0124 s:0040 e:000039 l:y n:0001 METHOD test/run_tests.rb:127 c:0005 p:0013 s:0024 E:001ca0 l:y n:0001 METHOD test/run_tests.rb:167 c:0004 p:1134 s:0016 e:000015 l:y n:0001 TOP /home/eregon/code/ractor-shim/test/test_ractor.rb:1941 [FINISH] c:0003 p:---- s:0012 e:000011 l:y n:---- CFUNC :require_relative c:0002 p:0107 s:0007 E:000cd8 l:n n:---- EVAL test/run_tests.rb:192 [FINISH] c:0001 p:0000 s:0003 E:0002d0 l:y n:---- DUMMY [FINISH] -- Ruby level backtrace information ---------------------------------------- test/run_tests.rb:192:in '<main>' test/run_tests.rb:192:in 'require_relative' /home/eregon/code/ractor-shim/test/test_ractor.rb:1941:in '<top (required)>' test/run_tests.rb:167:in 'assert_equal' test/run_tests.rb:127:in 'generic_assert' test/run_tests.rb:127:in 'catch' test/run_tests.rb:128:in 'block in generic_assert' test/run_tests.rb:128:in 'eval' /home/eregon/code/ractor-shim/test/test_ractor.rb:1946:in '<compiled>' <internal:ractor>:330:in 'send' <internal:ractor>:743:in 'send' -- Threading information --------------------------------------------------- Total ractor count: 2 Ruby thread count for this ractor: 1 -- C level backtrace information ------------------------------------------- /home/eregon/prefix/ruby-master/bin/ruby(rb_print_backtrace+0x14) [0x5630e371cb50] /home/eregon/code/ruby/vm_dump.c:1099 /home/eregon/prefix/ruby-master/bin/ruby(rb_vm_bugreport) /home/eregon/code/ruby/vm_dump.c:1444 /home/eregon/prefix/ruby-master/bin/ruby(rb_bug_without_die_internal+0x73) [0x5630e2fc554b] /home/eregon/code/ruby/error.c:1097 /home/eregon/prefix/ruby-master/bin/ruby(rb_bug) /home/eregon/code/ruby/error.c:1115 /home/eregon/prefix/ruby-master/bin/ruby(rb_imemo_fields_owner+0x0) [0x5630e2fa752b] /home/eregon/code/ruby/variable.c:1258 /home/eregon/prefix/ruby-master/bin/ruby(rb_obj_fields) /home/eregon/code/ruby/variable.c:1252 /home/eregon/prefix/ruby-master/bin/ruby(rb_shape_too_complex_p+0x0) [0x5630e31798f2] /home/eregon/code/ruby/variable.c:1812 /home/eregon/prefix/ruby-master/bin/ruby(imemo_fields_set) /home/eregon/code/ruby/variable.c:1766 /home/eregon/prefix/ruby-master/bin/ruby(generic_field_set) /home/eregon/code/ruby/variable.c:1813 /home/eregon/prefix/ruby-master/bin/ruby(RB_BUILTIN_TYPE+0x0) [0x5630e2fe8096] /home/eregon/code/ruby/gc.c:1900 /home/eregon/prefix/ruby-master/bin/ruby(rbimpl_RB_TYPE_P_fastpath) ./include/ruby/internal/value_type.h:352 /home/eregon/prefix/ruby-master/bin/ruby(RB_TYPE_P) ./include/ruby/internal/value_type.h:379 /home/eregon/prefix/ruby-master/bin/ruby(RBASIC_SHAPE_ID) ./shape.h:145 /home/eregon/prefix/ruby-master/bin/ruby(object_id0) /home/eregon/code/ruby/gc.c:1902 /home/eregon/prefix/ruby-master/bin/ruby(object_id0) /home/eregon/code/ruby/gc.c:1888 /home/eregon/prefix/ruby-master/bin/ruby(rb_gc_obj_id_moved+0x72) [0x5630e2fe8d52] /home/eregon/code/ruby/gc.c:2178 /home/eregon/prefix/ruby-master/bin/ruby(RB_IMMEDIATE_P+0x0) [0x5630e30943d0] /home/eregon/code/ruby/ractor.c:1977 /home/eregon/prefix/ruby-master/bin/ruby(RB_SPECIAL_CONST_P) ./include/ruby/internal/special_consts.h:329 /home/eregon/prefix/ruby-master/bin/ruby(rb_type) ./include/ruby/internal/value_type.h:227 /home/eregon/prefix/ruby-master/bin/ruby(rb_obj_exivar_p) /home/eregon/code/ruby/shape.h:422 /home/eregon/prefix/ruby-master/bin/ruby(move_leave) /home/eregon/code/ruby/ractor.c:1979 /home/eregon/prefix/ruby-master/bin/ruby(obj_traverse_replace_i+0x282) [0x5630e3097852] /home/eregon/code/ruby/ractor.c:1896 /home/eregon/prefix/ruby-master/bin/ruby(rb_obj_traverse_replace+0x46) [0x5630e3097f93] /home/eregon/code/ruby/ractor.c:1920 /home/eregon/prefix/ruby-master/bin/ruby(ractor_move) /home/eregon/code/ruby/ractor.c:1995 /home/eregon/prefix/ruby-master/bin/ruby(ractor_prepare_payload) /home/eregon/code/ruby/ractor_sync.c:787 /home/eregon/prefix/ruby-master/bin/ruby(ractor_basket_new) /home/eregon/code/ruby/ractor_sync.c:803 /home/eregon/prefix/ruby-master/bin/ruby(ractor_send0) /home/eregon/code/ruby/ractor_sync.c:1210 /home/eregon/prefix/ruby-master/bin/ruby(ractor_send) /home/eregon/code/ruby/ractor_sync.c:1219 /home/eregon/prefix/ruby-master/bin/ruby(ractor_port_send) /home/eregon/code/ruby/ractor_sync.c:150 /home/eregon/prefix/ruby-master/bin/ruby(builtin_inline_class_743) /home/eregon/code/ruby/ractor.rb:744 /home/eregon/prefix/ruby-master/bin/ruby(vm_pop_frame+0x0) [0x5630e31b148e] /home/eregon/code/ruby/vm_insnhelper.c:7550 /home/eregon/prefix/ruby-master/bin/ruby(vm_exec_core) /home/eregon/code/ruby/insns.def:1677 /home/eregon/prefix/ruby-master/bin/ruby(vm_exec_loop+0x52) [0x5630e31a1e0a] /home/eregon/code/ruby/vm.c:2769 /home/eregon/prefix/ruby-master/bin/ruby(rb_vm_exec) /home/eregon/code/ruby/vm.c:2745 /home/eregon/prefix/ruby-master/bin/ruby(rb_f_eval+0x163) [0x5630e31bc783] /home/eregon/code/ruby/vm_eval.c:2026 /home/eregon/prefix/ruby-master/bin/ruby(vm_cfp_consistent_p+0x0) [0x5630e3198f0d] /home/eregon/code/ruby/vm_insnhelper.c:3915 /home/eregon/prefix/ruby-master/bin/ruby(vm_call_cfunc_with_frame_) /home/eregon/code/ruby/vm_insnhelper.c:3917 /home/eregon/prefix/ruby-master/bin/ruby(vm_sendish+0x15f) [0x5630e3196d7f] /home/eregon/code/ruby/vm_insnhelper.c:6108 /home/eregon/prefix/ruby-master/bin/ruby(vm_exec_core+0x86) [0x5630e31b0e86] /home/eregon/code/ruby/insns.def:902 /home/eregon/prefix/ruby-master/bin/ruby(vm_exec_loop+0x52) [0x5630e31a1e0a] /home/eregon/code/ruby/vm.c:2769 /home/eregon/prefix/ruby-master/bin/ruby(rb_vm_exec) /home/eregon/code/ruby/vm.c:2745 /home/eregon/prefix/ruby-master/bin/ruby(catch_i+0xf7) [0x5630e31a6a07] /home/eregon/code/ruby/vm.c:1823 /home/eregon/prefix/ruby-master/bin/ruby(vm_catch_protect+0x118) [0x5630e319a6f8] /home/eregon/code/ruby/vm_eval.c:2634 /home/eregon/prefix/ruby-master/bin/ruby(rb_catch_obj+0x4a) [0x5630e319aa4f] /home/eregon/code/ruby/vm_eval.c:2660 /home/eregon/prefix/ruby-master/bin/ruby(rb_f_catch) /home/eregon/code/ruby/vm_eval.c:2610 /home/eregon/prefix/ruby-master/bin/ruby(vm_cfp_consistent_p+0x0) [0x5630e3198f0d] /home/eregon/code/ruby/vm_insnhelper.c:3915 /home/eregon/prefix/ruby-master/bin/ruby(vm_call_cfunc_with_frame_) /home/eregon/code/ruby/vm_insnhelper.c:3917 /home/eregon/prefix/ruby-master/bin/ruby(vm_sendish+0x15f) [0x5630e3196d7f] /home/eregon/code/ruby/vm_insnhelper.c:6108 /home/eregon/prefix/ruby-master/bin/ruby(vm_exec_core+0x147) [0x5630e31b0f47] /home/eregon/code/ruby/insns.def:854 /home/eregon/prefix/ruby-master/bin/ruby(vm_exec_loop+0x52) [0x5630e31a1e0a] /home/eregon/code/ruby/vm.c:2769 /home/eregon/prefix/ruby-master/bin/ruby(rb_vm_exec) /home/eregon/code/ruby/vm.c:2745 /home/eregon/prefix/ruby-master/bin/ruby(require_internal+0x10b2) [0x5630e303fe62] /home/eregon/code/ruby/load.c:1353 /home/eregon/prefix/ruby-master/bin/ruby(rb_require_string_internal+0x6e) [0x5630e303ff6e] /home/eregon/code/ruby/load.c:1464 /home/eregon/prefix/ruby-master/bin/ruby(vm_cfp_consistent_p+0x0) [0x5630e3198f0d] /home/eregon/code/ruby/vm_insnhelper.c:3915 /home/eregon/prefix/ruby-master/bin/ruby(vm_call_cfunc_with_frame_) /home/eregon/code/ruby/vm_insnhelper.c:3917 /home/eregon/prefix/ruby-master/bin/ruby(vm_sendish+0x15f) [0x5630e3196d7f] /home/eregon/code/ruby/vm_insnhelper.c:6108 /home/eregon/prefix/ruby-master/bin/ruby(vm_exec_core+0x86) [0x5630e31b0e86] /home/eregon/code/ruby/insns.def:902 /home/eregon/prefix/ruby-master/bin/ruby(vm_exec_loop+0x52) [0x5630e31a1e0a] /home/eregon/code/ruby/vm.c:2769 /home/eregon/prefix/ruby-master/bin/ruby(rb_vm_exec) /home/eregon/code/ruby/vm.c:2745 /home/eregon/prefix/ruby-master/bin/ruby(rb_ec_exec_node+0xd9) [0x5630e2fc9d99] /home/eregon/code/ruby/eval.c:283 /home/eregon/prefix/ruby-master/bin/ruby(ruby_run_node+0x80) [0x5630e2fce470] /home/eregon/code/ruby/eval.c:321 /home/eregon/prefix/ruby-master/bin/ruby(rb_main+0x21) [0x5630e2fc7180] ./main.c:42 /home/eregon/prefix/ruby-master/bin/ruby(main) ./main.c:62 /lib64/libc.so.6(__libc_start_call_main+0x78) [0x7fc19cb8b448] /lib64/libc.so.6(__libc_start_main+0x8b) [0x7fc19cb8b50b] [0x5630e2fc71c5] -- Other runtime information ----------------------------------------------- ... ``` -- https://bugs.ruby-lang.org/