All objects: sections are not shown sometimes

The sigdump often (about 50%?) does not show `all objects` section.

The output of sigdump stops at `Built-in objects:` section as below:

```
/xxxxxx/shared/bundle/ruby/2.2.0/gems/celluloid-0.16.0/lib/celluloid/tasks.rb:57:in `block in initialize'
/xxxxxx/shared/bundle/ruby/2.2.0/gems/celluloid-0.16.0/lib/celluloid/tasks/task_fiber.rb:15:in `block in create'
Built-in objects:
873,884: TOTAL
438,910: T_STRING
255,922: T_ARRAY
70,682: T_DATA
59,217: T_NODE
14,511: FREE
11,218: T_HASH
10,058: T_OBJECT
6,142: T_CLASS
2,052: T_REGEXP
1,367: T_ICLASS
984: T_RATIONAL
889: T_MODULE
816: T_STRUCT
567: T_BIGNUM
442: T_SYMBOL
82: T_MATCH
15: T_FILE
9: T_FLOAT
1: T_COMPLEX
```

I did not investigate well.