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fix SEGV inspecting uninitialized objects

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 #2: 0x00000001000c25ff miniruby`rb_iseq_path(iseq=0x00000001025b71a8) + 32 at iseq.c:723
    frame #3: 0x000000010009db09 miniruby`rb_raw_iseq_info(buff="0x00000001025b7158 [0    ] proc (Proc)", buff_size=256, iseq=0x00000001025b71a8) + 69 at gc.c:9274
    frame #4: 0x000000010009e1d5 miniruby`rb_raw_obj_info(buff="0x00000001025b7158 [0    ] proc (Proc)", buff_size=256, obj=4334514520) + 1546 at gc.c:9351
    frame #5: 0x000000010009e4d5 miniruby`obj_info(obj=4334514520) + 98 at gc.c:9429
    frame #6: 0x0000000100096658 miniruby`gc_writebarrier_incremental(a=4334514520, b=4334514600, objspace=0x00000001007d3280) + 61 at gc.c:5963
    frame #7: 0x00000001000968ca miniruby`rb_gc_writebarrier(a=4334514520, b=4334514600) + 127 at gc.c:6009
    frame #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 #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 #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 #11: 0x0000000100208e5c miniruby`rb_vm_make_proc_lambda(ec=0x00000001007d3548, captured=0x0000000102500338, klass=4311027960, is_lambda='\x01') + 134 at vm.c:892
    frame #12: 0x000000010011f08e miniruby`proc_new(klass=4311027960, is_lambda='\x01') + 445 at proc.c:752
    frame #13: 0x000000010011f110 miniruby`rb_block_lambda + 27 at proc.c:808
    frame #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 #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 #16: 0x00000001002034d9 miniruby`vm_call0_cfunc(ec=0x00000001007d3548, calling=0x00007fff5fbfb080, ci=0x00007fff5fbfb070, cc=0x00007fff5fbfb0a0, argv=0x0000000000000000) + 59 at vm_eval.c:100
    frame #17: 0x000000010020368f miniruby`vm_call0_body(ec=0x00000001007d3548, calling=0x00007fff5fbfb080, ci=0x00007fff5fbfb070, cc=0x00007fff5fbfb0a0, argv=0x0000000000000000) + 436 at vm_eval.c:131
    frame #18: 0x000000010020326a miniruby`vm_call0(ec=0x00000001007d3548, recv=4310991600, id=2993, argc=0, argv=0x0000000000000000, me=0x0000000100f48110) + 142 at vm_eval.c:58
    frame #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 #21: 0x000000010020518b miniruby`rb_funcallv(recv=4310991600, mid=2993, argc=0, argv=0x0000000000000000) + 52 at vm_eval.c:815
    frame #22: 0x000000010012242e miniruby`mlambda(method=0) + 45 at proc.c:2661
    frame #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 #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 #25: 0x00000001001224c7 miniruby`method_to_proc(method=4334514640) + 43 at proc.c:2701
    frame #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 #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 #28: 0x00000001001f30d6 miniruby`vm_call_cfunc(ec=0x00000001007d3548, reg_cfp=0x0000000102500350, calling=0x00007fff5fbfc030, ci=0x0000000100f2ec70, cc=0x0000000102735718) + 149 at vm_insnhelper.c:1934
    frame #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 #30: 0x00000001001f49a4 miniruby`vm_call_method(ec=0x00000001007d3548, cfp=0x0000000102500350, calling=0x00007fff5fbfc030, ci=0x0000000100f2ec70, cc=0x0000000102735718) + 117 at vm_insnhelper.c:2355
    frame #31: 0x00000001001f4b7a miniruby`vm_call_general(ec=0x00000001007d3548, reg_cfp=0x0000000102500350, calling=0x00007fff5fbfc030, ci=0x0000000100f2ec70, cc=0x0000000102735718) + 59 at vm_insnhelper.c:2398
    frame #32: 0x00000001001faf0e miniruby`vm_exec_core(ec=0x00000001007d3548, initial=0) + 8471 at insns.def:915
    frame #33: 0x000000010020b75d miniruby`vm_exec(ec=0x00000001007d3548) + 230 at vm.c:1771
    frame #34: 0x000000010020c3d1 miniruby`rb_iseq_eval(iseq=0x00000001007f8270) + 52 at vm.c:2008
    frame #35: 0x00000001000caa4a miniruby`rb_load_internal0(ec=0x00000001007d3548, fname=4310799960, wrap=0) + 631 at load.c:611
    frame #36: 0x00000001000cab36 miniruby`rb_load_internal(fname=4310799960, wrap=0) + 46 at load.c:642
    frame #37: 0x00000001000cae1d miniruby`rb_f_load(argc=1, argv=0x00000001024004b8) + 217 at load.c:710
    frame #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 #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 #40: 0x00000001001f30d6 miniruby`vm_call_cfunc(ec=0x00000001007d3548, reg_cfp=0x00000001025003e0, calling=0x00007fff5fbfd3e0, ci=0x0000000102541070, cc=0x0000000100f9e918) + 149 at vm_insnhelper.c:1934
    frame #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 #42: 0x00000001001f4a2c miniruby`vm_call_method(ec=0x00000001007d3548, cfp=0x00000001025003e0, calling=0x00007fff5fbfd3e0, ci=0x0000000102541070, cc=0x0000000100f9e918) + 253 at vm_insnhelper.c:2366
    frame #43: 0x00000001001f4b7a miniruby`vm_call_general(ec=0x00000001007d3548, reg_cfp=0x00000001025003e0, calling=0x00007fff5fbfd3e0, ci=0x0000000102541070, cc=0x0000000100f9e918) + 59 at vm_insnhelper.c:2398
    frame #44: 0x00000001001faf0e miniruby`vm_exec_core(ec=0x00000001007d3548, initial=0) + 8471 at insns.def:915
    frame #45: 0x000000010020b75d miniruby`vm_exec(ec=0x00000001007d3548) + 230 at vm.c:1771
    frame #46: 0x000000010020c40f miniruby`rb_iseq_eval_main(iseq=0x0000000100f21240) + 52 at vm.c:2019
    frame #47: 0x000000010007c774 miniruby`ruby_exec_internal(n=0x0000000100f21240) + 297 at eval.c:246
    frame #48: 0x000000010007c89a miniruby`ruby_exec_node(n=0x0000000100f21240) + 36 at eval.c:310
    frame #49: 0x000000010007c86d miniruby`ruby_run_node(n=0x0000000100f21240) + 62 at eval.c:302
    frame #50: 0x0000000100001399 miniruby`main(argc=9, argv=0x00007fff5fbfdae0) + 113 at main.c:42
    frame #51: 0x00007fff88eda5ad libdyld.dylib`start + 1
(lldb)

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61569 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
  • Loading branch information...
shyouhei committed Jan 2, 2018
1 parent 1d4129d commit 5b184f27867928830555d3335401cf4b3ca62f56
Showing with 4 additions and 4 deletions.
  1. +4 −4 gc.c
View
8 gc.c
@@ -5960,26 +5960,26 @@ NOINLINE(static void gc_writebarrier_incremental(VALUE a, VALUE b, rb_objspace_t
static void
gc_writebarrier_incremental(VALUE a, VALUE b, rb_objspace_t *objspace)
{
gc_report(2, objspace, "gc_writebarrier_incremental: [LG] %s -> %s\n", obj_info(a), obj_info(b));
gc_report(2, objspace, "gc_writebarrier_incremental: [LG] %p -> %s\n", (void *)a, obj_info(b));
if (RVALUE_BLACK_P(a)) {
if (RVALUE_WHITE_P(b)) {
if (!RVALUE_WB_UNPROTECTED(a)) {
gc_report(2, objspace, "gc_writebarrier_incremental: [IN] %s -> %s\n", obj_info(a), obj_info(b));
gc_report(2, objspace, "gc_writebarrier_incremental: [IN] %p -> %s\n", (void *)a, obj_info(b));
gc_mark_from(objspace, b, a);
}
}
else if (RVALUE_OLD_P(a) && !RVALUE_OLD_P(b)) {
if (!RVALUE_WB_UNPROTECTED(b)) {
gc_report(1, objspace, "gc_writebarrier_incremental: [GN] %s -> %s\n", obj_info(a), obj_info(b));
gc_report(1, objspace, "gc_writebarrier_incremental: [GN] %p -> %s\n", (void *)a, obj_info(b));
RVALUE_AGE_SET_OLD(objspace, b);
if (RVALUE_BLACK_P(b)) {
gc_grey(objspace, b);
}
}
else {
gc_report(1, objspace, "gc_writebarrier_incremental: [LL] %s -> %s\n", obj_info(a), obj_info(b));
gc_report(1, objspace, "gc_writebarrier_incremental: [LL] %p -> %s\n", (void *)a, obj_info(b));
gc_remember_unprotected(objspace, b);
}
}

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