Issue #10803 has been updated by Gabriel Mazetto.


Here is the C-level backtrace:
~~~

-- C level backtrace information -------------------------------------------
0   ruby                                0x00000001018f4270 rb_vm_bugreport + 144
1   ruby                                0x00000001017a5f11 report_bug + 305
2   ruby                                0x00000001017a5dd4 rb_bug + 180
3   ruby                                0x00000001017c6a69 gc_mark_children + 2409
4   ruby                                0x00000001017cdeaf gc_marks_body + 479
5   ruby                                0x00000001017cbd1b garbage_collect_body + 859
6   ruby                                0x00000001017c4a97 garbage_collect + 407
7   ruby                                0x00000001017cb32d garbage_collect_with_gvl + 61
8   ruby                                0x00000001017c7254 objspace_xmalloc + 196
9   ruby                                0x000000010188017e st_update + 1310
10  ruby                                0x00000001017cf5e1 tbl_update + 65
11  ruby                                0x00000001017cf551 rb_hash_aset + 241
12  syck.bundle                         0x0000000101e630d5 rb_syck_load_handler + 293
13  syck.bundle                         0x0000000101e5e3f8 syck_hdlr_add_node + 24
14  syck.bundle                         0x0000000101e5dda4 syckparse + 2612
15  syck.bundle                         0x0000000101e67f58 syck_parse + 248
16  syck.bundle                         0x0000000101e63484 syck_parser_load + 212
17  ruby                                0x00000001018f2a77 vm_call_cfunc + 1063
18  ruby                                0x00000001018d9b4d vm_exec_core + 11933
19  ruby                                0x00000001018e8541 vm_exec + 129
20  ruby                                0x00000001018ed175 invoke_block_from_c + 2213
21  ruby                                0x00000001018e4d58 rb_yield + 184
22  ruby                                0x00000001017af6aa rb_ensure + 170
23  ruby                                0x00000001018f2a77 vm_call_cfunc + 1063
24  ruby                                0x00000001018d9983 vm_exec_core + 11475
25  ruby                                0x00000001018e8541 vm_exec + 129
26  ruby                                0x00000001018ed175 invoke_block_from_c + 2213
27  ruby                                0x00000001018e4f18 rb_yield_values + 408
28  ruby                                0x00000001017d42dc each_pair_i_fast + 28
29  ruby                                0x00000001017d4af5 hash_foreach_iter + 37
30  ruby                                0x000000010188050e st_foreach_check + 718
31  ruby                                0x00000001017ce482 hash_foreach_call + 34
32  ruby                                0x00000001017af6aa rb_ensure + 170
33  ruby                                0x00000001017d1da8 rb_hash_each_pair + 184
34  ruby                                0x00000001018f2a77 vm_call_cfunc + 1063
35  ruby                                0x00000001018d9983 vm_exec_core + 11475
36  ruby                                0x00000001018e8541 vm_exec + 129
37  ruby                                0x00000001018ed175 invoke_block_from_c + 2213
38  ruby                                0x00000001018e4d58 rb_yield + 184
39  ruby                                0x000000010176bde9 rb_ary_each + 73
40  ruby                                0x00000001018f2a77 vm_call_cfunc + 1063
41  ruby                                0x00000001018f23c2 vm_call_method + 866
42  ruby                                0x00000001018f338c vm_call_opt_send + 588
43  ruby                                0x00000001018d9983 vm_exec_core + 11475
44  ruby                                0x00000001018e8541 vm_exec + 129
45  ruby                                0x00000001018ed175 invoke_block_from_c + 2213
46  ruby                                0x00000001018e4d58 rb_yield + 184
47  ruby                                0x00000001017a0101 each_slice_i + 97
48  ruby                                0x00000001018ecb2a invoke_block_from_c + 602
49  ruby                                0x00000001018e4d58 rb_yield + 184
50  ruby                                0x000000010176bde9 rb_ary_each + 73
51  ruby                                0x00000001018f0150 vm_call0_body + 2320
52  ruby                                0x00000001018e54b8 iterate_method + 216
53  ruby                                0x00000001018e52f9 rb_iterate + 441
54  ruby                                0x00000001018e53cd rb_block_call + 45
55  ruby                                0x000000010179e584 enum_each_slice + 116
56  ruby                                0x00000001018f2a77 vm_call_cfunc + 1063
57  ruby                                0x00000001018f23c2 vm_call_method + 866
58  ruby                                0x00000001018d9983 vm_exec_core + 11475
59  ruby                                0x00000001018e8541 vm_exec + 129
60  ruby                                0x00000001018eeeef eval_string_with_cref + 1631
61  ruby                                0x00000001018e5741 rb_f_eval + 161
62  ruby                                0x00000001018f2a77 vm_call_cfunc + 1063
63  ruby                                0x00000001018d9b4d vm_exec_core + 11933
64  ruby                                0x00000001018e8541 vm_exec + 129
65  ruby                                0x00000001018ed175 invoke_block_from_c + 2213
66  ruby                                0x00000001018ee7c1 loop_i + 49
67  ruby                                0x00000001017af356 rb_rescue2 + 278
68  ruby                                0x00000001018e6a93 rb_f_loop + 51
69  ruby                                0x00000001018f2a77 vm_call_cfunc + 1063
70  ruby                                0x00000001018f23c2 vm_call_method + 866
71  ruby                                0x00000001018d9983 vm_exec_core + 11475
72  ruby                                0x00000001018e8541 vm_exec + 129
73  ruby                                0x00000001018ed175 invoke_block_from_c + 2213
74  ruby                                0x00000001018ee868 catch_i + 88
75  ruby                                0x00000001018e6479 rb_catch_protect + 185
76  ruby                                0x00000001018e6a0c rb_f_catch + 76
77  ruby                                0x00000001018f2a77 vm_call_cfunc + 1063
78  ruby                                0x00000001018f23c2 vm_call_method + 866
79  ruby                                0x00000001018d9983 vm_exec_core + 11475
80  ruby                                0x00000001018e8541 vm_exec + 129
81  ruby                                0x00000001018ed175 invoke_block_from_c + 2213
82  ruby                                0x00000001018ee868 catch_i + 88
83  ruby                                0x00000001018e6479 rb_catch_protect + 185
84  ruby                                0x00000001018e6a0c rb_f_catch + 76
85  ruby                                0x00000001018f2a77 vm_call_cfunc + 1063
86  ruby                                0x00000001018f23c2 vm_call_method + 866
87  ruby                                0x00000001018d9983 vm_exec_core + 11475
88  ruby                                0x00000001018e8541 vm_exec + 129
89  ruby                                0x00000001018e8480 rb_iseq_eval + 288
90  ruby                                0x00000001017b3687 rb_load_internal0 + 311
91  ruby                                0x00000001017b2c7e rb_require_safe + 1598
92  ruby                                0x00000001018f2a77 vm_call_cfunc + 1063
93  ruby                                0x00000001018f23c2 vm_call_method + 866
94  ruby                                0x00000001018d9b4d vm_exec_core + 11933
95  ruby                                0x00000001018e8541 vm_exec + 129
96  ruby                                0x00000001018e94cc rb_iseq_eval_main + 396
97  ruby                                0x00000001017ae7e4 ruby_exec_internal + 148
98  ruby                                0x00000001017ae70e ruby_run_node + 78
99  ruby                                0x00000001017694ef main + 79

-- Other runtime information -----------------------------------------------
~~~

----------------------------------------
Bug #10803: 2.1.5: rb_gc_mark()
https://bugs.ruby-lang.org/issues/10803#change-51304

* Author: Gabriel Mazetto
* Status: Open
* Priority: Normal
* Assignee: 
* ruby -v: ruby 2.1.5p273 (2014-11-13 revision 48405) [x86_64-darwin14.0]
* Backport: 2.0.0: UNKNOWN, 2.1: UNKNOWN, 2.2: UNKNOWN
----------------------------------------
~~~
/opt/rubies/2.1.5/lib/ruby/gems/2.1.0/bundler/gems/syck-358913870211/lib/syck.rb:136: [BUG] rb_gc_mark(): 0x007f96aa63a888 is T_NONE
ruby 2.1.5p273 (2014-11-13 revision 48405) [x86_64-darwin14.0]

-- Control frame information -----------------------------------------------
c:0053 p:---- s:0202 e:000201 CFUNC  :load
c:0052 p:0011 s:0198 e:000197 METHOD /opt/rubies/2.1.5/lib/ruby/gems/2.1.0/bundler/gems/syck-358913870211/lib/syck.rb:136
c:0051 p:0009 s:0194 e:000193 BLOCK  /opt/rubies/2.1.5/lib/ruby/gems/2.1.0/bundler/gems/syck-358913870211/lib/syck.rb:147 [FINISH]
c:0050 p:---- s:0191 e:000190 CFUNC  :open
c:0049 p:0015 s:0187 e:000186 METHOD /opt/rubies/2.1.5/lib/ruby/gems/2.1.0/bundler/gems/syck-358913870211/lib/syck.rb:146
c:0048 p:0044 s:0183 e:000182 METHOD /myapp/app/models/component/default_field.rb:46
c:0047 p:0021 s:0180 e:000179 METHOD /myapp/app/models/component/default_field.rb:42
c:0046 p:0007 s:0177 e:000176 METHOD /myapp/app/models/component/default_field.rb:4
c:0045 p:0031 s:0174 e:000173 BLOCK  /myapp/app/models/conversion/content_processor.rb:26 [FINISH]
c:0044 p:---- s:0169 e:000168 CFUNC  :each
c:0043 p:0011 s:0166 e:000165 METHOD /myapp/app/models/conversion/content_processor.rb:24
c:0042 p:0013 s:0163 e:000162 METHOD /myapp/app/models/conversion/content_processor.rb:14
c:0041 p:0034 s:0160 e:000159 METHOD /myapp/app/models/conversion/conversion_importer.rb:32
c:0040 p:0032 s:0155 e:000153 BLOCK  /myapp/app/models/conversion/conversion_importer.rb:26 [FINISH]
c:0039 p:---- s:0151 e:000150 CFUNC  :each
c:0038 p:0015 s:0148 e:000147 METHOD /opt/rubies/2.1.5/lib/ruby/gems/2.1.0/gems/activerecord-3.2.18/lib/active_record/relation/delegation.rb:6
c:0037 p:0015 s:0143 E:001c30 METHOD /myapp/app/models/conversion/conversion_importer.rb:24
c:0036 p:0007 s:0139 e:000138 METHOD /myapp/app/models/conversion/conversion_importer.rb:10
c:0035 p:0073 s:0135 e:000134 METHOD /myapp/app/models/conversion/lead_importer.rb:45
c:0034 p:0019 s:0132 e:000131 METHOD /myapp/app/models/conversion/lead_importer.rb:15
c:0033 p:0030 s:0129 e:000128 METHOD /myapp/app/models/conversion.rb:83
c:0032 p:0026 s:0126 e:000125 METHOD /myapp/app/models/conversion.rb:17
c:0031 p:0031 s:0122 e:000121 BLOCK  /myapp/app/models/lead/import.rb:206
c:0030 p:0193 s:0119 e:000118 METHOD /opt/rubies/2.1.5/lib/ruby/gems/2.1.0/gems/activerecord-3.2.18/lib/active_record/connection_adapters/abstract/database_statemen
c:0029 p:0017 s:0110 e:000109 METHOD /opt/rubies/2.1.5/lib/ruby/gems/2.1.0/gems/activerecord-3.2.18/lib/active_record/transactions.rb:208
c:0028 p:0015 s:0105 E:000700 BLOCK  /myapp/app/models/lead/import.rb:204 [FINISH]
c:0027 p:---- s:0102 e:000101 IFUNC
c:0026 p:---- s:0100 e:000099 CFUNC  :each
c:0025 p:---- s:0098 e:000097 CFUNC  :each_slice
c:0024 p:0024 s:0094 E:000958 METHOD /myapp/app/models/lead/import.rb:203
c:0023 p:0014 s:0091 E:000e48 METHOD /myapp/app/models/lead/import.rb:98
c:0022 p:0006 s:0088 E:001af8 EVAL   (irb):2 [FINISH]
c:0021 p:---- s:0086 e:000085 CFUNC  :eval
c:0020 p:0024 s:0079 E:0019b8 METHOD /opt/rubies/2.1.5/lib/ruby/2.1.0/irb/workspace.rb:86
c:0019 p:0025 s:0072 E:001a28 METHOD /opt/rubies/2.1.5/lib/ruby/2.1.0/irb/context.rb:380
c:0018 p:0022 s:0066 E:001b28 BLOCK  /opt/rubies/2.1.5/lib/ruby/2.1.0/irb.rb:492
c:0017 p:0040 s:0058 E:001be8 METHOD /opt/rubies/2.1.5/lib/ruby/2.1.0/irb.rb:624
c:0016 p:0009 s:0053 E:001a98 BLOCK  /opt/rubies/2.1.5/lib/ruby/2.1.0/irb.rb:489
c:0015 p:0118 s:0049 E:000a60 BLOCK  /opt/rubies/2.1.5/lib/ruby/2.1.0/irb/ruby-lex.rb:247 [FINISH]
c:0014 p:---- s:0046 e:000045 CFUNC  :loop
c:0013 p:0007 s:0043 E:000338 BLOCK  /opt/rubies/2.1.5/lib/ruby/2.1.0/irb/ruby-lex.rb:233 [FINISH]
c:0012 p:---- s:0041 e:000040 CFUNC  :catch
c:0011 p:0015 s:0037 E:000358 METHOD /opt/rubies/2.1.5/lib/ruby/2.1.0/irb/ruby-lex.rb:232
c:0010 p:0030 s:0034 E:002438 METHOD /opt/rubies/2.1.5/lib/ruby/2.1.0/irb.rb:488
c:0009 p:0008 s:0031 E:001468 BLOCK  /opt/rubies/2.1.5/lib/ruby/2.1.0/irb.rb:397 [FINISH]
c:0008 p:---- s:0029 e:000028 CFUNC  :catch
c:0007 p:0143 s:0025 E:0011e8 METHOD /opt/rubies/2.1.5/lib/ruby/2.1.0/irb.rb:396
c:0006 p:0195 s:0020 E:0026f0 METHOD /opt/rubies/2.1.5/lib/ruby/gems/2.1.0/gems/railties-3.2.18/lib/rails/commands/console.rb:47
c:0005 p:0011 s:0016 E:0006a0 METHOD /opt/rubies/2.1.5/lib/ruby/gems/2.1.0/gems/railties-3.2.18/lib/rails/commands/console.rb:8
c:0004 p:0426 s:0012 E:0022c8 TOP    /opt/rubies/2.1.5/lib/ruby/gems/2.1.0/gems/railties-3.2.18/lib/rails/commands.rb:41 [FINISH]
c:0003 p:---- s:0008 e:000007 CFUNC  :require
c:0002 p:0045 s:0004 E:000be8 EVAL   script/rails:5 [FINISH]
c:0001 p:0000 s:0002 E:000b18 TOP    [FINISH]
~~~

I've experienced this problem with other gems that have C extensions, it's not deterministic.



-- 
https://bugs.ruby-lang.org/