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…e into empty slots on CoW shared pages
jamatthews
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Jan 27, 2018
This function can be called from boot_defclass(). No assumption can be made about object internals. (lldb) run Process 2386 launched: './miniruby' (x86_64) Process 2386 stopped * thread #1: tid = 0x13f3b6, 0x00000001001e0b26 miniruby`rb_class_path_cached(klass=4311373720) + 20 at variable.c:321, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x8) frame #0: 0x00000001001e0b26 miniruby`rb_class_path_cached(klass=4311373720) + 20 at variable.c:321 318 VALUE 319 rb_class_path_cached(VALUE klass) 320 { -> 321 st_table *ivtbl = RCLASS_IV_TBL(klass); 322 st_data_t n; 323 324 if (!ivtbl) return Qnil; (lldb) bt * thread #1: tid = 0x13f3b6, 0x00000001001e0b26 miniruby`rb_class_path_cached(klass=4311373720) + 20 at variable.c:321, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x8) * frame #0: 0x00000001001e0b26 miniruby`rb_class_path_cached(klass=4311373720) + 20 at variable.c:321 frame #1: 0x000000010009cbd0 miniruby`rb_raw_obj_info(buff="0x0000000100fa5798 [2 ] T_CLASS", buff_size=256, obj=4311373720) + 1393 at gc.c:9341 frame ruby#2: 0x000000010009cf16 miniruby`obj_info(obj=4311373720) + 98 at gc.c:9423 frame ruby#3: 0x000000010008ca87 miniruby`newobj_init(klass=0, flags=66, v1=0, v2=0, v3=0, wb_protected=1, objspace=0x00000001007cf280, obj=4311373720) + 338 at gc.c:1887 frame ruby#4: 0x000000010008cd51 miniruby`newobj_of(klass=0, flags=66, v1=0, v2=0, v3=0, wb_protected=1) + 171 at gc.c:1970 frame ruby#5: 0x000000010008ce1b miniruby`rb_wb_protected_newobj_of(klass=0, flags=66) + 54 at gc.c:1990 frame ruby#6: 0x0000000100027563 miniruby`class_alloc(flags=2, klass=0) + 46 at class.c:165 frame ruby#7: 0x000000010002761a miniruby`rb_class_boot(super=0) + 35 at class.c:203 frame ruby#8: 0x0000000100028612 miniruby`boot_defclass(name="BasicObject", super=0) + 28 at class.c:537 frame ruby#9: 0x000000010002868b miniruby`Init_class_hierarchy + 26 at class.c:548 frame ruby#10: 0x00000001000efe69 miniruby`InitVM_Object + 9 at object.c:3892 frame ruby#11: 0x00000001000f138e miniruby`Init_Object + 57 at object.c:4122 frame ruby#12: 0x00000001000a59bd miniruby`rb_call_inits + 29 at inits.c:23 frame ruby#13: 0x000000010007af30 miniruby`ruby_setup + 229 at eval.c:61 frame ruby#14: 0x000000010007af7e miniruby`ruby_init + 13 at eval.c:78 frame ruby#15: 0x0000000100000c58 miniruby`main(argc=2, argv=0x00007fff5fbfdbf0) + 88 at main.c:41 frame ruby#16: 0x00007fff88eda5ad libdyld.dylib`start + 1 (lldb) git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61562 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
jamatthews
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Jan 27, 2018
This function can be called from InitVM_Object(). No assumption can be made about object internals. (lldb) run Process 10675 launched: './miniruby' (x86_64) Process 10675 stopped * thread #1: tid = 0x14252c, 0x00000001000bdda9 miniruby`rb_raw_obj_info(buff="0x0000000100fc1588 [0 ] T_IMEMO ment", buff_size=256, obj=4311487880) + 2489 at gc.c:9383, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x0) frame #0: 0x00000001000bdda9 miniruby`rb_raw_obj_info(buff="0x0000000100fc1588 [0 ] T_IMEMO ment", buff_size=256, obj=4311487880) + 2489 at gc.c:9383 9380 const rb_method_entry_t *me = &RANY(obj)->as.imemo.ment; 9381 snprintf(buff, buff_size, "%s (called_id: %s, type: %s, alias: %d, owner: %s, defined_class: %s)", buff, 9382 rb_id2name(me->called_id), -> 9383 method_type_name(me->def->type), 9384 me->def->alias_count, 9385 obj_info(me->owner), 9386 obj_info(me->defined_class)); (lldb) p *me (rb_method_entry_t) $0 = { flags = 24602 defined_class = 4311488400 def = 0x0000000000000000 called_id = 3057 owner = 4311488400 } (lldb) bt * thread #1: tid = 0x14252c, 0x00000001000bdda9 miniruby`rb_raw_obj_info(buff="0x0000000100fc1588 [0 ] T_IMEMO ment", buff_size=256, obj=4311487880) + 2489 at gc.c:9383, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x0) * frame #0: 0x00000001000bdda9 miniruby`rb_raw_obj_info(buff="0x0000000100fc1588 [0 ] T_IMEMO ment", buff_size=256, obj=4311487880) + 2489 at gc.c:9383 frame #1: 0x00000001000b7cbf miniruby`obj_info(obj=4311487880) + 95 at gc.c:9423 frame ruby#2: 0x00000001000c16a8 miniruby`newobj_init(klass=4311488400, flags=24602, v1=0, v2=3057, v3=4311488400, wb_protected=1, objspace=0x00000001007ee280, obj=4311487880) + 424 at gc.c:1887 frame ruby#3: 0x00000001000b4529 miniruby`newobj_of(klass=4311488400, flags=24602, v1=0, v2=3057, v3=4311488400, wb_protected=1) + 217 at gc.c:1970 frame ruby#4: 0x00000001000b46ab miniruby`rb_imemo_new(type=imemo_ment, v1=0, v2=3057, v3=4311488400, v0=4311488400) + 75 at gc.c:2017 frame ruby#5: 0x00000001002773b4 miniruby`rb_method_entry_alloc(called_id=3057, owner=4311488400, defined_class=4311488400, def=0x0000000000000000) + 52 at vm_method.c:368 frame ruby#6: 0x0000000100277307 miniruby`rb_method_entry_create(called_id=3057, klass=4311488400, visi=METHOD_VISI_PRIVATE, def=0x0000000000000000) + 71 at vm_method.c:389 frame ruby#7: 0x00000001002784c7 miniruby`rb_method_entry_make(klass=4311488400, mid=3057, defined_class=4311488400, visi=METHOD_VISI_PRIVATE, type=VM_METHOD_TYPE_CFUNC, def=0x0000000000000000, original_id=3057, opts=0x00007fff5fbfd9e8) + 1207 at vm_method.c:594 frame ruby#8: 0x00000001002770f9 miniruby`rb_add_method(klass=4311488400, mid=3057, type=VM_METHOD_TYPE_CFUNC, opts=0x00007fff5fbfd9e8, visi=METHOD_VISI_PRIVATE) + 73 at vm_method.c:650 frame ruby#9: 0x000000010027708a miniruby`rb_add_method_cfunc(klass=4311488400, mid=3057, func=(miniruby`rb_obj_dummy at object.c:1125), argc=0, visi=METHOD_VISI_PRIVATE) + 138 at vm_method.c:137 frame ruby#10: 0x00000001000391e4 miniruby`rb_define_private_method(klass=4311488400, name="initialize", func=(miniruby`rb_obj_dummy at object.c:1125), argc=0) + 68 at class.c:1529 frame ruby#11: 0x000000010013f5bf miniruby`InitVM_Object + 47 at object.c:3905 frame ruby#12: 0x0000000100142ffd miniruby`Init_Object + 61 at object.c:4122 frame ruby#13: 0x00000001000d4edd miniruby`rb_call_inits + 29 at inits.c:23 frame ruby#14: 0x000000010009fe66 miniruby`ruby_setup + 198 at eval.c:61 frame ruby#15: 0x000000010009febd miniruby`ruby_init + 13 at eval.c:78 frame ruby#16: 0x0000000100000a4d miniruby`main(argc=2, argv=0x00007fff5fbfdbf0) + 93 at main.c:41 frame ruby#17: 0x00007fff88eda5ad libdyld.dylib`start + 1 (lldb) git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61563 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
jamatthews
pushed a commit
that referenced
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Jan 27, 2018
This function can be called from Init_VM(). No assumption can be made about object internals. (lldb) run Process 15734 launched: './miniruby' (x86_64) Process 15734 stopped * thread #1: tid = 0x1441d4, 0x00000001000bdfcb miniruby`rb_raw_iseq_info(buff="0x0000000100f61f48 [0 ] T_IMEMO iseq", buff_size=256, iseq=0x0000000100f61f48) + 27 at gc.c:9273, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x50) frame #0: 0x00000001000bdfcb miniruby`rb_raw_iseq_info(buff="0x0000000100f61f48 [0 ] T_IMEMO iseq", buff_size=256, iseq=0x0000000100f61f48) + 27 at gc.c:9273 9270 static void 9271 rb_raw_iseq_info(char *buff, const int buff_size, const rb_iseq_t *iseq) 9272 { -> 9273 if (iseq->body->location.label) { 9274 VALUE path = rb_iseq_path(iseq); 9275 snprintf(buff, buff_size, "%s %s@%s:%d", buff, 9276 RSTRING_PTR(iseq->body->location.label), (lldb) p *iseq (rb_iseq_t) $0 = { flags = 28698 reserved1 = 0 body = 0x0000000000000000 aux = { compile_data = 0x0000000000000000 loader = (obj = 0, index = 0) trace_events = 0 } } (lldb) bt * thread #1: tid = 0x1441d4, 0x00000001000bdfcb miniruby`rb_raw_iseq_info(buff="0x0000000100f61f48 [0 ] T_IMEMO iseq", buff_size=256, iseq=0x0000000100f61f48) + 27 at gc.c:9273, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x50) * frame #0: 0x00000001000bdfcb miniruby`rb_raw_iseq_info(buff="0x0000000100f61f48 [0 ] T_IMEMO iseq", buff_size=256, iseq=0x0000000100f61f48) + 27 at gc.c:9273 frame #1: 0x00000001000bde72 miniruby`rb_raw_obj_info(buff="0x0000000100f61f48 [0 ] T_IMEMO iseq", buff_size=256, obj=4311097160) + 2786 at gc.c:9396 frame ruby#2: 0x00000001000b7c5f miniruby`obj_info(obj=4311097160) + 95 at gc.c:9428 frame ruby#3: 0x00000001000c16a8 miniruby`newobj_init(klass=0, flags=28698, v1=0, v2=0, v3=0, wb_protected=1, objspace=0x00000001007ee280, obj=4311097160) + 424 at gc.c:1887 frame ruby#4: 0x00000001000b44c9 miniruby`newobj_of(klass=0, flags=28698, v1=0, v2=0, v3=0, wb_protected=1) + 217 at gc.c:1970 frame ruby#5: 0x00000001000b464b miniruby`rb_imemo_new(type=imemo_iseq, v1=0, v2=0, v3=0, v0=0) + 75 at gc.c:2017 frame ruby#6: 0x00000001000fd914 miniruby`iseq_imemo_alloc + 36 at iseq.h:156 frame ruby#7: 0x00000001000f6e1d miniruby`iseq_alloc + 13 at iseq.c:211 frame ruby#8: 0x00000001000f6bf8 miniruby`rb_iseq_new_with_opt(node=0x0000000000000000, name=4311097200, path=4311097200, realpath=8, first_lineno=1, parent=0x0000000000000000, type=ISEQ_TYPE_TOP, option=0x0000000100335c30) + 56 at iseq.c:519 frame ruby#9: 0x00000001000f6bb6 miniruby`rb_iseq_new(node=0x0000000000000000, name=4311097200, path=4311097200, realpath=8, parent=0x0000000000000000, type=ISEQ_TYPE_TOP) + 86 at iseq.c:480 frame ruby#10: 0x0000000100284bb0 miniruby`Init_VM + 1040 at vm.c:3022 frame ruby#11: 0x00000001000d4f7d miniruby`rb_call_inits + 189 at inits.c:55 frame ruby#12: 0x000000010009fe06 miniruby`ruby_setup + 198 at eval.c:61 frame ruby#13: 0x000000010009fe5d miniruby`ruby_init + 13 at eval.c:78 frame ruby#14: 0x00000001000009ed miniruby`main(argc=2, argv=0x00007fff5fbfdbf0) + 93 at main.c:41 frame ruby#15: 0x00007fff88eda5ad libdyld.dylib`start + 1 (lldb) git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61564 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
jamatthews
pushed a commit
that referenced
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Jan 27, 2018
This function can be called from rb_data_typed_object_zalloc(). No assumption can be made about object internals. (lldb) run Process 22135 launched: './miniruby' (x86_64) Process 22135 stopped * thread #1: tid = 0x14a3af, 0x000000010008ac8a miniruby`vm_block_type(block=0x0000000000000000) + 12 at vm_core.h:1364, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x18) frame #0: 0x000000010008ac8a miniruby`vm_block_type(block=0x0000000000000000) + 12 at vm_core.h:1364 1361 break; 1362 } 1363 #endif -> 1364 return block->type; 1365 } 1366 1367 static inline void (lldb) bt * thread #1: tid = 0x14a3af, 0x000000010008ac8a miniruby`vm_block_type(block=0x0000000000000000) + 12 at vm_core.h:1364, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x18) * frame #0: 0x000000010008ac8a miniruby`vm_block_type(block=0x0000000000000000) + 12 at vm_core.h:1364 frame #1: 0x000000010008acdb miniruby`vm_block_iseq(block=0x0000000000000000) + 24 at vm_core.h:1399 frame ruby#2: 0x000000010008acc1 miniruby`vm_proc_iseq(procval=4310866360) + 32 at vm_core.h:1387 frame ruby#3: 0x000000010009cbed miniruby`rb_raw_obj_info(buff="0x0000000100f299b8 [0 ] proc (Proc)", buff_size=256, obj=4310866360) + 1513 at gc.c:9349 frame ruby#4: 0x000000010009cf01 miniruby`obj_info(obj=4310866360) + 98 at gc.c:9428 frame ruby#5: 0x000000010008ca1b miniruby`newobj_init(klass=4311027960, flags=12, v1=4298186080, v2=1, v3=0, wb_protected=32, objspace=0x00000001007cf280, obj=4310866360) + 338 at gc.c:1887 frame ruby#6: 0x000000010008cce5 miniruby`newobj_of(klass=4311027960, flags=12, v1=4298186080, v2=1, v3=0, wb_protected=32) + 171 at gc.c:1970 frame ruby#7: 0x000000010008d01d miniruby`rb_data_typed_object_wrap(klass=4311027960, datap=0x0000000000000000, type=0x0000000100311d60) + 133 at gc.c:2062 frame ruby#8: 0x000000010008d04e miniruby`rb_data_typed_object_zalloc(klass=4311027960, size=40, type=0x0000000100311d60) + 42 at gc.c:2073 frame ruby#9: 0x000000010011b459 miniruby`rb_proc_alloc(klass=4311027960) + 36 at proc.c:113 frame ruby#10: 0x0000000100204d8e miniruby`vm_proc_create_from_captured(klass=4311027960, captured=0x00000001025003f8, block_type=block_type_iseq, is_from_method='\0', is_lambda='\x01') + 44 at vm.c:814 frame ruby#11: 0x00000001002050d8 miniruby`rb_vm_make_proc_lambda(ec=0x00000001007cf548, captured=0x00000001025003f8, klass=4311027960, is_lambda='\x01') + 134 at vm.c:892 frame ruby#12: 0x000000010011c0d2 miniruby`proc_new(klass=4311027960, is_lambda='\x01') + 445 at proc.c:752 frame ruby#13: 0x000000010011c154 miniruby`rb_block_lambda + 27 at proc.c:808 frame ruby#14: 0x00000001001ee7e3 miniruby`call_cfunc_0(func=(miniruby`rb_block_lambda at proc.c:807), recv=4310991600, argc=0, argv=0x0000000102400480) + 41 at vm_insnhelper.c:1729 frame ruby#15: 0x00000001001ef2c3 miniruby`vm_call_cfunc_with_frame(ec=0x00000001007cf548, reg_cfp=0x00000001025003e0, calling=0x00007fff5fbfd4d0, ci=0x0000000102537be0, cc=0x000000010253e0f0) + 386 at vm_insnhelper.c:1918 frame ruby#16: 0x00000001001ef412 miniruby`vm_call_cfunc(ec=0x00000001007cf548, reg_cfp=0x00000001025003e0, calling=0x00007fff5fbfd4d0, ci=0x0000000102537be0, cc=0x000000010253e0f0) + 149 at vm_insnhelper.c:1934 frame ruby#17: 0x00000001001f0655 miniruby`vm_call_method_each_type(ec=0x00000001007cf548, cfp=0x00000001025003e0, calling=0x00007fff5fbfd4d0, ci=0x0000000102537be0, cc=0x000000010253e0f0) + 239 at vm_insnhelper.c:2232 frame ruby#18: 0x00000001001f0ce0 miniruby`vm_call_method(ec=0x00000001007cf548, cfp=0x00000001025003e0, calling=0x00007fff5fbfd4d0, ci=0x0000000102537be0, cc=0x000000010253e0f0) + 117 at vm_insnhelper.c:2355 frame ruby#19: 0x00000001001f0eb6 miniruby`vm_call_general(ec=0x00000001007cf548, reg_cfp=0x00000001025003e0, calling=0x00007fff5fbfd4d0, ci=0x0000000102537be0, cc=0x000000010253e0f0) + 59 at vm_insnhelper.c:2398 frame #20: 0x00000001001f6e61 miniruby`vm_exec_core(ec=0x00000001007cf548, initial=0) + 7480 at insns.def:850 frame ruby#21: 0x0000000100207995 miniruby`vm_exec(ec=0x00000001007cf548) + 230 at vm.c:1771 frame ruby#22: 0x0000000100208647 miniruby`rb_iseq_eval_main(iseq=0x0000000100f29fd0) + 52 at vm.c:2019 frame ruby#23: 0x000000010007b750 miniruby`ruby_exec_internal(n=0x0000000100f29fd0) + 297 at eval.c:246 frame ruby#24: 0x000000010007b876 miniruby`ruby_exec_node(n=0x0000000100f29fd0) + 36 at eval.c:310 frame ruby#25: 0x000000010007b849 miniruby`ruby_run_node(n=0x0000000100f29fd0) + 62 at eval.c:302 frame ruby#26: 0x0000000100000c05 miniruby`main(argc=2, argv=0x00007fff5fbfdbf0) + 113 at main.c:42 frame ruby#27: 0x00007fff88eda5ad libdyld.dylib`start + 1 (lldb) git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61565 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
jamatthews
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that referenced
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Jan 27, 2018
This imemo_name is used uninitialized because the switch above does not cover all possible imemo types. (lldb) run Process 26068 launched: './miniruby' (x86_64) Process 26068 stopped * thread #1: tid = 0x14ba96, 0x00007fff8a402132 libsystem_c.dylib`strlen + 18, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0xfffffffffffffff0) frame #0: 0x00007fff8a402132 libsystem_c.dylib`strlen + 18 libsystem_c.dylib`strlen: -> 0x7fff8a402132 <+18>: pcmpeqb (%rdi), %xmm0 0x7fff8a402136 <+22>: pmovmskb %xmm0, %esi 0x7fff8a40213a <+26>: andq $0xf, %rcx 0x7fff8a40213e <+30>: orq $-0x1, %rax (lldb) bt * thread #1: tid = 0x14ba96, 0x00007fff8a402132 libsystem_c.dylib`strlen + 18, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0xfffffffffffffff0) * frame #0: 0x00007fff8a402132 libsystem_c.dylib`strlen + 18 frame #1: 0x00000001001f1531 miniruby`BSD_vfprintf(fp=0x00007fff5fbfc9e0, fmt0="%s %s", ap=0x00007fff5fbfcbf0) + 5873 at vsnprintf.c:1026 frame ruby#2: 0x00000001001ef213 miniruby`ruby_do_vsnprintf(str="0x0000000100f46450 [0 ] T_IMEMO", n=256, fmt="%s %s", ap=0x00007fff5fbfcbf0) + 131 at sprintf.c:1285 frame ruby#3: 0x00000001001ef3ea miniruby`ruby_snprintf(str="0x0000000100f46450 [0 ] T_IMEMO", n=256, fmt="%s %s") + 426 at sprintf.c:1300 frame ruby#4: 0x00000001000bdc61 miniruby`rb_raw_obj_info(buff="0x0000000100f46450 [0 ] T_IMEMO", buff_size=256, obj=4310983760) + 2353 at gc.c:9376 frame ruby#5: 0x00000001000b7bff miniruby`obj_info(obj=4310983760) + 95 at gc.c:9428 frame ruby#6: 0x00000001000c1658 miniruby`newobj_init(klass=0, flags=36890, v1=0, v2=4303040512, v3=4310983800, wb_protected=1, objspace=0x00000001007ee280, obj=4310983760) + 424 at gc.c:1887 frame ruby#7: 0x00000001000b4469 miniruby`newobj_of(klass=0, flags=36890, v1=0, v2=4303040512, v3=4310983800, wb_protected=1) + 217 at gc.c:1970 frame ruby#8: 0x00000001000b45eb miniruby`rb_imemo_new(type=imemo_ast, v1=0, v2=4303040512, v3=4310983800, v0=0) + 75 at gc.c:2017 frame ruby#9: 0x000000010011daed miniruby`rb_ast_new + 61 at node.c:1146 frame ruby#10: 0x0000000100160e15 miniruby`rb_parser_compile_file_path(vparser=4310984400, fname=4310984960, file=4310984080, start=1) + 53 at parse.y:5776 frame ruby#11: 0x00000001001e18ea miniruby`load_file_internal(argp_v=140734799795024) + 1834 at ruby.c:1907 frame ruby#12: 0x00000001000a1bb5 miniruby`rb_ensure(b_proc=(miniruby`load_file_internal at ruby.c:1795), data1=140734799795024, e_proc=(miniruby`restore_load_file at ruby.c:2007), data2=140734799795024) + 245 at eval.c:1037 frame ruby#13: 0x00000001001df4a4 miniruby`load_file(parser=4310984400, fname=4310984960, f=4310984080, script=1, opt=0x00007fff5fbfda28) + 100 at ruby.c:2026 frame ruby#14: 0x00000001001e084e miniruby`process_options(argc=0, argv=0x00007fff5fbfdc00, opt=0x00007fff5fbfda28) + 3454 at ruby.c:1682 frame ruby#15: 0x00000001001dfaae miniruby`ruby_process_options(argc=2, argv=0x00007fff5fbfdbf0) + 238 at ruby.c:2257 frame ruby#16: 0x000000010009ff43 miniruby`ruby_options(argc=2, argv=0x00007fff5fbfdbf0) + 211 at eval.c:105 frame ruby#17: 0x0000000100000989 miniruby`main(argc=2, argv=0x00007fff5fbfdbf0) + 105 at main.c:42 frame ruby#18: 0x00007fff88eda5ad libdyld.dylib`start + 1 (lldb) up 4 frame ruby#4: 0x00000001000bdc61 miniruby`rb_raw_obj_info(buff="0x0000000100f46450 [0 ] T_IMEMO", buff_size=256, obj=4310983760) + 2353 at gc.c:9376 9373 #undef IMEMO_NAME 9374 default: UNREACHABLE; 9375 } -> 9376 snprintf(buff, buff_size, "%s %s", buff, imemo_name); 9377 9378 switch (imemo_type(obj)) { 9379 case imemo_ment: { (lldb) p imemo_name (const char *) $0 = 0xffffffffffffffff (lldb) p imemo_type(obj) (imemo_type) $1 = imemo_ast (lldb) git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61566 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
jamatthews
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Jan 27, 2018
obj_info() assumes the given object is alive. Passing freed objects to it results in SEGV. (lldb) run Process 29718 launched: './miniruby' (x86_64) Process 29718 stopped * thread #1: tid = 0x3082c5, 0x00000001000bfaab miniruby`pathobj_path(pathobj=4478683640) + 70 at vm_core.h:269, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x0) frame #0: 0x00000001000bfaab miniruby`pathobj_path(pathobj=4478683640) + 70 at vm_core.h:269 266 } 267 else { 268 VM_ASSERT(RB_TYPE_P(pathobj, T_ARRAY)); -> 269 return RARRAY_AREF(pathobj, PATHOBJ_PATH); 270 } 271 } 272 (lldb) bt * thread #1: tid = 0x3082c5, 0x00000001000bfaab miniruby`pathobj_path(pathobj=4478683640) + 70 at vm_core.h:269, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x0) * frame #0: 0x00000001000bfaab miniruby`pathobj_path(pathobj=4478683640) + 70 at vm_core.h:269 frame #1: 0x00000001000c25ff miniruby`rb_iseq_path(iseq=0x000000010af34a20) + 32 at iseq.c:723 frame ruby#2: 0x000000010009db09 miniruby`rb_raw_iseq_info(buff="0x000000010af34a20 [1 ] T_IMEMO iseq", buff_size=256, iseq=0x000000010af34a20) + 69 at gc.c:9274 frame ruby#3: 0x000000010009e45a miniruby`rb_raw_obj_info(buff="0x000000010af34a20 [1 ] T_IMEMO iseq", buff_size=256, obj=4478683680) + 2191 at gc.c:9397 frame ruby#4: 0x000000010009e4d5 miniruby`obj_info(obj=4478683680) + 98 at gc.c:9429 frame ruby#5: 0x0000000100091ae3 miniruby`gc_page_sweep(objspace=0x00000001007d3280, heap=0x00000001007d32a0, sweep_page=0x000000010ae07bc0) + 622 at gc.c:3529 frame ruby#6: 0x000000010009206a miniruby`gc_sweep_step(objspace=0x00000001007d3280, heap=0x00000001007d32a0) + 188 at gc.c:3705 frame ruby#7: 0x0000000100092254 miniruby`gc_sweep_continue(objspace=0x00000001007d3280, heap=0x00000001007d32a0) + 133 at gc.c:3772 frame ruby#8: 0x000000010008d7f9 miniruby`heap_prepare(objspace=0x00000001007d3280, heap=0x00000001007d32a0) + 48 at gc.c:1746 frame ruby#9: 0x000000010008d8a1 miniruby`heap_get_freeobj_from_next_freepage(objspace=0x00000001007d3280, heap=0x00000001007d32a0) + 37 at gc.c:1769 frame ruby#10: 0x000000010008d98d miniruby`heap_get_freeobj(objspace=0x00000001007d3280, heap=0x00000001007d32a0) + 83 at gc.c:1803 frame ruby#11: 0x000000010008dcb0 miniruby`newobj_slowpath(klass=4334386280, flags=5, v1=0, v2=0, v3=0, objspace=0x00000001007d3280, wb_protected=1) + 220 at gc.c:1930 frame ruby#12: 0x000000010008dd6c miniruby`newobj_slowpath_wb_protected(klass=4334386280, flags=5, v1=0, v2=0, v3=0, objspace=0x00000001007d3280) + 76 at gc.c:1942 frame ruby#13: 0x000000010008dea1 miniruby`newobj_of(klass=4334386280, flags=5, v1=0, v2=0, v3=0, wb_protected=1) + 221 at gc.c:1974 frame ruby#14: 0x000000010008df39 miniruby`rb_wb_protected_newobj_of(klass=4334386280, flags=5) + 54 at gc.c:1990 frame ruby#15: 0x0000000100195f7c miniruby`str_alloc(klass=4334386280) + 29 at string.c:692 frame ruby#16: 0x0000000100195fe9 miniruby`str_new0(klass=4334386280, ptr="gitm", len=4, termlen=1) + 73 at string.c:714 frame ruby#17: 0x000000010019633e miniruby`rb_enc_str_new(ptr="gitm", len=4, enc=0x00000001025d50a0) + 81 at string.c:766 frame ruby#18: 0x000000010010a80a miniruby`parser_str_new(p="gitm", n=4, enc=0x00000001025d50a0, func=66, enc0=0x00000001025d50a0) + 50 at parse.y:5817 frame ruby#19: 0x000000010010ce1a miniruby`parser_parse_string(parser=0x00000001042ac5c0, quote=0x000000010460c028) + 795 at parse.y:6675 frame #20: 0x00000001001120bd miniruby`parser_yylex(parser=0x00000001042ac5c0) + 159 at parse.y:8281 frame ruby#21: 0x0000000100115068 miniruby`yylex(lval=0x00007fff5fbf9948, yylloc=0x00007fff5fbf9ab0, parser=0x00000001042ac5c0) + 55 at parse.y:8931 frame ruby#22: 0x00000001000fc79f miniruby`ruby_yyparse(parser=0x00000001042ac5c0) + 1198 at parse.c:5798 frame ruby#23: 0x0000000100109f5a miniruby`yycompile0(arg=4364879296) + 317 at parse.y:5595 frame ruby#24: 0x0000000100214ef0 miniruby`rb_suppress_tracing(func=(miniruby`yycompile0 at parse.y:5565), arg=4364879296) + 349 at vm_trace.c:397 frame ruby#25: 0x000000010010a1df miniruby`yycompile(parser=0x00000001042ac5c0, fname=4443743440, line=1) + 126 at parse.y:5637 frame ruby#26: 0x000000010010a4c1 miniruby`parser_compile_string(vparser=4443743480, fname=4443743440, s=4443743520, line=1) + 191 at parse.y:5706 frame ruby#27: 0x000000010010a5b7 miniruby`rb_parser_compile_string_path(vparser=4443743480, f=4443743440, s=4443743520, line=1) + 58 at parse.y:5730 frame ruby#28: 0x0000000100206025 miniruby`eval_make_iseq(src=4443743520, fname=4443743440, line=1, bind=0x0000000000000000, base_block=0x00007fff5fbfb370) + 266 at vm_eval.c:1274 frame ruby#29: 0x0000000100206153 miniruby`eval_string_with_cref(self=4334412520, src=4443743520, cref=0x0000000000000000, file=52, line=1) + 197 at vm_eval.c:1307 frame ruby#30: 0x0000000100206389 miniruby`rb_f_eval(argc=1, argv=0x0000000102400eb8, self=4334412520) + 219 at vm_eval.c:1382 frame ruby#31: 0x00000001001f247c miniruby`call_cfunc_m1(func=(miniruby`rb_f_eval at vm_eval.c:1364), recv=4334412520, argc=1, argv=0x0000000102400eb8) + 47 at vm_insnhelper.c:1723 frame ruby#32: 0x00000001001f2f87 miniruby`vm_call_cfunc_with_frame(ec=0x00000001007d3548, reg_cfp=0x0000000102500d80, calling=0x00007fff5fbfbf50, ci=0x000000010263f240, cc=0x0000000100749b50) + 386 at vm_insnhelper.c:1918 frame ruby#33: 0x00000001001f30d6 miniruby`vm_call_cfunc(ec=0x00000001007d3548, reg_cfp=0x0000000102500d80, calling=0x00007fff5fbfbf50, ci=0x000000010263f240, cc=0x0000000100749b50) + 149 at vm_insnhelper.c:1934 frame ruby#34: 0x00000001001faf0e miniruby`vm_exec_core(ec=0x00000001007d3548, initial=0) + 8471 at insns.def:915 frame ruby#35: 0x000000010020b75d miniruby`vm_exec(ec=0x00000001007d3548) + 230 at vm.c:1771 frame ruby#36: 0x00000001002093f8 miniruby`invoke_block(ec=0x00000001007d3548, iseq=0x000000010252d7f0, self=4334412520, captured=0x0000000102500df8, cref=0x0000000000000000, type=572653569, opt_pc=0) + 224 at vm.c:988 frame ruby#37: 0x0000000100209766 miniruby`invoke_iseq_block_from_c(ec=0x00000001007d3548, captured=0x0000000102500df8, self=4334412520, argc=0, argv=0x0000000000000000, passed_block_handler=0, cref=0x0000000000000000, is_lambda=0) + 389 at vm.c:1040 frame ruby#38: 0x0000000100209824 miniruby`invoke_block_from_c_bh(ec=0x00000001007d3548, block_handler=4333768185, argc=0, argv=0x0000000000000000, passed_block_handler=0, cref=0x0000000000000000, is_lambda=0, force_blockarg=0) + 138 at vm.c:1058 frame ruby#39: 0x00000001002099d0 miniruby`vm_yield(ec=0x00000001007d3548, argc=0, argv=0x0000000000000000) + 69 at vm.c:1103 frame ruby#40: 0x0000000100205623 miniruby`rb_yield_0(argc=0, argv=0x0000000000000000) + 40 at vm_eval.c:970 frame ruby#41: 0x0000000100205964 miniruby`loop_i + 19 at vm_eval.c:1049 frame ruby#42: 0x000000010007db07 miniruby`rb_rescue2(b_proc=(miniruby`loop_i at vm_eval.c:1047), data1=0, r_proc=(miniruby`loop_stop at vm_eval.c:1056), data2=0) + 369 at eval.c:896 frame ruby#43: 0x0000000100205a2e miniruby`rb_f_loop(self=4334412520) + 121 at vm_eval.c:1100 frame ruby#44: 0x00000001001f24a7 miniruby`call_cfunc_0(func=(miniruby`rb_f_loop at vm_eval.c:1098), recv=4334412520, argc=0, argv=0x0000000102400e80) + 41 at vm_insnhelper.c:1729 frame ruby#45: 0x00000001001f2f87 miniruby`vm_call_cfunc_with_frame(ec=0x00000001007d3548, reg_cfp=0x0000000102500de0, calling=0x00007fff5fbfd4d0, ci=0x000000010263bbf0, cc=0x0000000102642118) + 386 at vm_insnhelper.c:1918 frame ruby#46: 0x00000001001f30d6 miniruby`vm_call_cfunc(ec=0x00000001007d3548, reg_cfp=0x0000000102500de0, calling=0x00007fff5fbfd4d0, ci=0x000000010263bbf0, cc=0x0000000102642118) + 149 at vm_insnhelper.c:1934 frame ruby#47: 0x00000001001f4319 miniruby`vm_call_method_each_type(ec=0x00000001007d3548, cfp=0x0000000102500de0, calling=0x00007fff5fbfd4d0, ci=0x000000010263bbf0, cc=0x0000000102642118) + 239 at vm_insnhelper.c:2232 frame ruby#48: 0x00000001001f4a2c miniruby`vm_call_method(ec=0x00000001007d3548, cfp=0x0000000102500de0, calling=0x00007fff5fbfd4d0, ci=0x000000010263bbf0, cc=0x0000000102642118) + 253 at vm_insnhelper.c:2366 frame ruby#49: 0x00000001001f4b7a miniruby`vm_call_general(ec=0x00000001007d3548, reg_cfp=0x0000000102500de0, calling=0x00007fff5fbfd4d0, ci=0x000000010263bbf0, cc=0x0000000102642118) + 59 at vm_insnhelper.c:2398 frame ruby#50: 0x00000001001fab2f miniruby`vm_exec_core(ec=0x00000001007d3548, initial=0) + 7480 at insns.def:850 frame ruby#51: 0x000000010020b75d miniruby`vm_exec(ec=0x00000001007d3548) + 230 at vm.c:1771 frame ruby#52: 0x000000010020c40f miniruby`rb_iseq_eval_main(iseq=0x000000010252dd90) + 52 at vm.c:2019 frame ruby#53: 0x000000010007c768 miniruby`ruby_exec_internal(n=0x000000010252dd90) + 297 at eval.c:246 frame ruby#54: 0x000000010007c88e miniruby`ruby_exec_node(n=0x000000010252dd90) + 36 at eval.c:310 frame ruby#55: 0x000000010007c861 miniruby`ruby_run_node(n=0x000000010252dd90) + 62 at eval.c:302 frame ruby#56: 0x000000010000138d miniruby`main(argc=2, argv=0x00007fff5fbfdbf0) + 113 at main.c:42 frame ruby#57: 0x00007fff88eda5ad libdyld.dylib`start + 1 (lldb) p ((struct RVALUE*)pathobj)->as.basic (RBasic) $0 = (flags = 0, klass = 4478683600) (lldb) git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61568 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
jamatthews
pushed a commit
that referenced
this pull request
Jan 27, 2018
obj_info() assumes the given object is alive. OTOH gc_writebarrier_incremental is called before or in middle of object initialization. Can casue SEGV. (lldb) run Process 48188 launched: './miniruby' (x86_64) Process 48188 stopped * thread #1: tid = 0x30fd53, 0x00000001000bf7a9 miniruby`rb_array_const_ptr(a=5251291222225483145) + 12 at ruby.h:2072, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT) frame #0: 0x00000001000bf7a9 miniruby`rb_array_const_ptr(a=5251291222225483145) + 12 at ruby.h:2072 2069 static inline const VALUE * 2070 rb_array_const_ptr(VALUE a) 2071 { -> 2072 return FIX_CONST_VALUE_PTR((RBASIC(a)->flags & RARRAY_EMBED_FLAG) ? 2073 RARRAY(a)->as.ary : RARRAY(a)->as.heap.ptr); 2074 } 2075 (lldb) bt * thread #1: tid = 0x30fd53, 0x00000001000bf7a9 miniruby`rb_array_const_ptr(a=5251291222225483145) + 12 at ruby.h:2072, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT) * frame #0: 0x00000001000bf7a9 miniruby`rb_array_const_ptr(a=5251291222225483145) + 12 at ruby.h:2072 frame #1: 0x00000001000bfaab miniruby`pathobj_path(pathobj=5251291222225483145) + 70 at vm_core.h:269 frame ruby#2: 0x00000001000c25ff miniruby`rb_iseq_path(iseq=0x00000001025b71a8) + 32 at iseq.c:723 frame ruby#3: 0x000000010009db09 miniruby`rb_raw_iseq_info(buff="0x00000001025b7158 [0 ] proc (Proc)", buff_size=256, iseq=0x00000001025b71a8) + 69 at gc.c:9274 frame ruby#4: 0x000000010009e1d5 miniruby`rb_raw_obj_info(buff="0x00000001025b7158 [0 ] proc (Proc)", buff_size=256, obj=4334514520) + 1546 at gc.c:9351 frame ruby#5: 0x000000010009e4d5 miniruby`obj_info(obj=4334514520) + 98 at gc.c:9429 frame ruby#6: 0x0000000100096658 miniruby`gc_writebarrier_incremental(a=4334514520, b=4334514600, objspace=0x00000001007d3280) + 61 at gc.c:5963 frame ruby#7: 0x00000001000968ca miniruby`rb_gc_writebarrier(a=4334514520, b=4334514600) + 127 at gc.c:6009 frame ruby#8: 0x00000001001eabe0 miniruby`rb_obj_written(a=4334514520, oldv=52, b=4334514600, filename="/Users/urabe.shyouhei/data/src/pedantic/vm.c", line=821) + 72 at ruby.h:1472 frame ruby#9: 0x00000001001eac2c miniruby`rb_obj_write(a=4334514520, slot=0x000000010259ff10, b=4334514600, filename="/Users/urabe.shyouhei/data/src/pedantic/vm.c", line=821) + 70 at ruby.h:1489 frame ruby#10: 0x0000000100208b6f miniruby`vm_proc_create_from_captured(klass=4311027960, captured=0x0000000102500338, block_type=block_type_ifunc, is_from_method='\0', is_lambda='\x01') + 137 at vm.c:821 frame ruby#11: 0x0000000100208e5c miniruby`rb_vm_make_proc_lambda(ec=0x00000001007d3548, captured=0x0000000102500338, klass=4311027960, is_lambda='\x01') + 134 at vm.c:892 frame ruby#12: 0x000000010011f08e miniruby`proc_new(klass=4311027960, is_lambda='\x01') + 445 at proc.c:752 frame ruby#13: 0x000000010011f110 miniruby`rb_block_lambda + 27 at proc.c:808 frame ruby#14: 0x00000001001f24a7 miniruby`call_cfunc_0(func=(miniruby`rb_block_lambda at proc.c:807), recv=4310991600, argc=0, argv=0x0000000000000000) + 41 at vm_insnhelper.c:1729 frame ruby#15: 0x00000001002033de miniruby`vm_call0_cfunc_with_frame(ec=0x00000001007d3548, calling=0x00007fff5fbfb080, ci=0x00007fff5fbfb070, cc=0x00007fff5fbfb0a0, argv=0x0000000000000000) + 370 at vm_eval.c:85 frame ruby#16: 0x00000001002034d9 miniruby`vm_call0_cfunc(ec=0x00000001007d3548, calling=0x00007fff5fbfb080, ci=0x00007fff5fbfb070, cc=0x00007fff5fbfb0a0, argv=0x0000000000000000) + 59 at vm_eval.c:100 frame ruby#17: 0x000000010020368f miniruby`vm_call0_body(ec=0x00000001007d3548, calling=0x00007fff5fbfb080, ci=0x00007fff5fbfb070, cc=0x00007fff5fbfb0a0, argv=0x0000000000000000) + 436 at vm_eval.c:131 frame ruby#18: 0x000000010020326a miniruby`vm_call0(ec=0x00000001007d3548, recv=4310991600, id=2993, argc=0, argv=0x0000000000000000, me=0x0000000100f48110) + 142 at vm_eval.c:58 frame ruby#19: 0x0000000100203c60 miniruby`rb_call0(ec=0x00000001007d3548, recv=4310991600, mid=2993, argc=0, argv=0x0000000000000000, scope=CALL_FCALL, self=4334514640) + 166 at vm_eval.c:296 frame #20: 0x0000000100204827 miniruby`rb_call(recv=4310991600, mid=2993, argc=0, argv=0x0000000000000000, scope=CALL_FCALL) + 84 at vm_eval.c:589 frame ruby#21: 0x000000010020518b miniruby`rb_funcallv(recv=4310991600, mid=2993, argc=0, argv=0x0000000000000000) + 52 at vm_eval.c:815 frame ruby#22: 0x000000010012242e miniruby`mlambda(method=0) + 45 at proc.c:2661 frame ruby#23: 0x0000000100205bac miniruby`rb_iterate0(it_proc=(miniruby`mlambda at proc.c:2660), data1=0, ifunc=0x00000001025b71a8, ec=0x00000001007d3548) + 380 at vm_eval.c:1134 frame ruby#24: 0x0000000100205d16 miniruby`rb_iterate(it_proc=(miniruby`mlambda at proc.c:2660), data1=0, bl_proc=(miniruby`bmcall at proc.c:2666), data2=4334514640) + 88 at vm_eval.c:1166 frame ruby#25: 0x00000001001224c7 miniruby`method_to_proc(method=4334514640) + 43 at proc.c:2701 frame ruby#26: 0x00000001001f24a7 miniruby`call_cfunc_0(func=(miniruby`method_to_proc at proc.c:2688), recv=4334514640, argc=0, argv=0x0000000102400568) + 41 at vm_insnhelper.c:1729 frame ruby#27: 0x00000001001f2f87 miniruby`vm_call_cfunc_with_frame(ec=0x00000001007d3548, reg_cfp=0x0000000102500350, calling=0x00007fff5fbfc030, ci=0x0000000100f2ec70, cc=0x0000000102735718) + 386 at vm_insnhelper.c:1918 frame ruby#28: 0x00000001001f30d6 miniruby`vm_call_cfunc(ec=0x00000001007d3548, reg_cfp=0x0000000102500350, calling=0x00007fff5fbfc030, ci=0x0000000100f2ec70, cc=0x0000000102735718) + 149 at vm_insnhelper.c:1934 frame ruby#29: 0x00000001001f4319 miniruby`vm_call_method_each_type(ec=0x00000001007d3548, cfp=0x0000000102500350, calling=0x00007fff5fbfc030, ci=0x0000000100f2ec70, cc=0x0000000102735718) + 239 at vm_insnhelper.c:2232 frame ruby#30: 0x00000001001f49a4 miniruby`vm_call_method(ec=0x00000001007d3548, cfp=0x0000000102500350, calling=0x00007fff5fbfc030, ci=0x0000000100f2ec70, cc=0x0000000102735718) + 117 at vm_insnhelper.c:2355 frame ruby#31: 0x00000001001f4b7a miniruby`vm_call_general(ec=0x00000001007d3548, reg_cfp=0x0000000102500350, calling=0x00007fff5fbfc030, ci=0x0000000100f2ec70, cc=0x0000000102735718) + 59 at vm_insnhelper.c:2398 frame ruby#32: 0x00000001001faf0e miniruby`vm_exec_core(ec=0x00000001007d3548, initial=0) + 8471 at insns.def:915 frame ruby#33: 0x000000010020b75d miniruby`vm_exec(ec=0x00000001007d3548) + 230 at vm.c:1771 frame ruby#34: 0x000000010020c3d1 miniruby`rb_iseq_eval(iseq=0x00000001007f8270) + 52 at vm.c:2008 frame ruby#35: 0x00000001000caa4a miniruby`rb_load_internal0(ec=0x00000001007d3548, fname=4310799960, wrap=0) + 631 at load.c:611 frame ruby#36: 0x00000001000cab36 miniruby`rb_load_internal(fname=4310799960, wrap=0) + 46 at load.c:642 frame ruby#37: 0x00000001000cae1d miniruby`rb_f_load(argc=1, argv=0x00000001024004b8) + 217 at load.c:710 frame ruby#38: 0x00000001001f247c miniruby`call_cfunc_m1(func=(miniruby`rb_f_load at load.c:695), recv=4311327440, argc=1, argv=0x00000001024004b8) + 47 at vm_insnhelper.c:1723 frame ruby#39: 0x00000001001f2f87 miniruby`vm_call_cfunc_with_frame(ec=0x00000001007d3548, reg_cfp=0x00000001025003e0, calling=0x00007fff5fbfd3e0, ci=0x0000000102541070, cc=0x0000000100f9e918) + 386 at vm_insnhelper.c:1918 frame ruby#40: 0x00000001001f30d6 miniruby`vm_call_cfunc(ec=0x00000001007d3548, reg_cfp=0x00000001025003e0, calling=0x00007fff5fbfd3e0, ci=0x0000000102541070, cc=0x0000000100f9e918) + 149 at vm_insnhelper.c:1934 frame ruby#41: 0x00000001001f4319 miniruby`vm_call_method_each_type(ec=0x00000001007d3548, cfp=0x00000001025003e0, calling=0x00007fff5fbfd3e0, ci=0x0000000102541070, cc=0x0000000100f9e918) + 239 at vm_insnhelper.c:2232 frame ruby#42: 0x00000001001f4a2c miniruby`vm_call_method(ec=0x00000001007d3548, cfp=0x00000001025003e0, calling=0x00007fff5fbfd3e0, ci=0x0000000102541070, cc=0x0000000100f9e918) + 253 at vm_insnhelper.c:2366 frame ruby#43: 0x00000001001f4b7a miniruby`vm_call_general(ec=0x00000001007d3548, reg_cfp=0x00000001025003e0, calling=0x00007fff5fbfd3e0, ci=0x0000000102541070, cc=0x0000000100f9e918) + 59 at vm_insnhelper.c:2398 frame ruby#44: 0x00000001001faf0e miniruby`vm_exec_core(ec=0x00000001007d3548, initial=0) + 8471 at insns.def:915 frame ruby#45: 0x000000010020b75d miniruby`vm_exec(ec=0x00000001007d3548) + 230 at vm.c:1771 frame ruby#46: 0x000000010020c40f miniruby`rb_iseq_eval_main(iseq=0x0000000100f21240) + 52 at vm.c:2019 frame ruby#47: 0x000000010007c774 miniruby`ruby_exec_internal(n=0x0000000100f21240) + 297 at eval.c:246 frame ruby#48: 0x000000010007c89a miniruby`ruby_exec_node(n=0x0000000100f21240) + 36 at eval.c:310 frame ruby#49: 0x000000010007c86d miniruby`ruby_run_node(n=0x0000000100f21240) + 62 at eval.c:302 frame ruby#50: 0x0000000100001399 miniruby`main(argc=9, argv=0x00007fff5fbfdae0) + 113 at main.c:42 frame ruby#51: 0x00007fff88eda5ad libdyld.dylib`start + 1 (lldb) git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61569 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
jamatthews
pushed a commit
that referenced
this pull request
Sep 12, 2020
This reverts commit 02b216e. This reverts commit 9b8825b. I found that combining sweep and move is not safe. I don't think that we can do compaction concurrently with _anything_ unless there is a read barrier installed. Here is a simple example. A class object is freed, and during it's free step, it tries to remove itself from its parent's subclass list. However, during the sweep step, the parent class was moved and the "currently being freed" class didn't have references updated yet. So we get a segv like this: ``` (lldb) bt * thread #1, name = 'ruby', stop reason = signal SIGSEGV * frame #0: 0x0000560763e344cb ruby`rb_st_lookup at st.c:320:43 frame #1: 0x0000560763e344cb ruby`rb_st_lookup(tab=0x2f7469672f6e6f72, key=3809, value=0x0000560765bf2270) at st.c:1010 frame ruby#2: 0x0000560763e8f16a ruby`rb_search_class_path at variable.c:99:9 frame ruby#3: 0x0000560763e8f141 ruby`rb_search_class_path at variable.c:145 frame ruby#4: 0x0000560763e8f141 ruby`rb_search_class_path(klass=94589785585880) at variable.c:191 frame ruby#5: 0x0000560763ec744e ruby`rb_vm_bugreport at vm_dump.c:996:17 frame ruby#6: 0x0000560763f5b958 ruby`rb_bug_for_fatal_signal at error.c:675:5 frame ruby#7: 0x0000560763e27dad ruby`sigsegv(sig=<unavailable>, info=<unavailable>, ctx=<unavailable>) at signal.c:955:5 frame ruby#8: 0x00007f8b891d33c0 libpthread.so.0`___lldb_unnamed_symbol1$$libpthread.so.0 + 1 frame ruby#9: 0x0000560763efa8bb ruby`rb_class_remove_from_super_subclasses(klass=94589790314280) at class.c:93:56 frame ruby#10: 0x0000560763d10cb7 ruby`gc_sweep_step at gc.c:2674:2 frame ruby#11: 0x0000560763d1187b ruby`gc_sweep at gc.c:4540:2 frame ruby#12: 0x0000560763d101f0 ruby`gc_start at gc.c:6797:6 frame ruby#13: 0x0000560763d15153 ruby`rb_gc_compact at gc.c:7479:12 frame ruby#14: 0x0000560763eb4eb8 ruby`vm_exec_core at vm_insnhelper.c:5183:13 frame ruby#15: 0x0000560763ea9bae ruby`rb_vm_exec at vm.c:1953:22 frame ruby#16: 0x0000560763eac08d ruby`rb_yield at vm.c:1132:9 frame ruby#17: 0x0000560763edb4f2 ruby`rb_ary_collect at array.c:3186:9 frame ruby#18: 0x0000560763e9ee15 ruby`vm_call_cfunc_with_frame at vm_insnhelper.c:2575:12 frame ruby#19: 0x0000560763eb2e66 ruby`vm_exec_core at vm_insnhelper.c:4177:11 frame #20: 0x0000560763ea9bae ruby`rb_vm_exec at vm.c:1953:22 frame ruby#21: 0x0000560763eac08d ruby`rb_yield at vm.c:1132:9 frame ruby#22: 0x0000560763edb4f2 ruby`rb_ary_collect at array.c:3186:9 frame ruby#23: 0x0000560763e9ee15 ruby`vm_call_cfunc_with_frame at vm_insnhelper.c:2575:12 frame ruby#24: 0x0000560763eb2e66 ruby`vm_exec_core at vm_insnhelper.c:4177:11 frame ruby#25: 0x0000560763ea9bae ruby`rb_vm_exec at vm.c:1953:22 frame ruby#26: 0x0000560763ceee01 ruby`rb_ec_exec_node(ec=0x0000560765afa530, n=0x0000560765b088e0) at eval.c:296:2 frame ruby#27: 0x0000560763cf3b7b ruby`ruby_run_node(n=0x0000560765b088e0) at eval.c:354:12 frame ruby#28: 0x0000560763cee4a3 ruby`main(argc=<unavailable>, argv=<unavailable>) at main.c:50:9 frame ruby#29: 0x00007f8b88e560b3 libc.so.6`__libc_start_main + 243 frame ruby#30: 0x0000560763cee4ee ruby`_start + 46 (lldb) f 9 frame ruby#9: 0x0000560763efa8bb ruby`rb_class_remove_from_super_subclasses(klass=94589790314280) at class.c:93:56 90 91 *RCLASS_EXT(klass)->parent_subclasses = entry->next; 92 if (entry->next) { -> 93 RCLASS_EXT(entry->next->klass)->parent_subclasses = RCLASS_EXT(klass)->parent_subclasses; 94 } 95 xfree(entry); 96 } (lldb) command script import -r misc/lldb_cruby.py lldb scripts for ruby has been installed. (lldb) rp entry->next->klass (struct RMoved) $1 = (flags = 30, destination = 94589792806680, next = 94589784369160) (lldb) ```
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The idea here is to flag pages to not write into in child processes, even if there are empty slots. As partially full pages are "free" to a child process, even if they have empty space it's more efficient to just allocate a new page for the child than to copy an already half full page from the parent.