From: Robert Klemme <bob.news@...>
Date: 2004-01-15T21:26:35+09:00
Subject: Re: YAML bug: ruby 1.8.1 (2003-12-05) [i686-linux]


"Andrew Walrond" <andrew@walrond.org> schrieb im Newsbeitrag
news:200401151124.23571.andrew@walrond.org...
> When dumping a Hash containing a string with a length greater than about
4100,
> ruby segfaults:
>
> ...
> 4099
> 4100
> 4101
> 4102
> 4103
> /pkg/ruby.2/lib/ruby/1.8/yaml.rb:193: [BUG] Segmentation fault
> ruby 1.8.1 (2003-12-05) [i686-linux]
>
> Easily reproduced here with simple test
>
> #!/bin/ruby
>
> require 'yaml'
>
> len = 1
> while true
>   a = {"test"=>'x'*len}
> puts len
> b = YAML.dump(a)
> len += 1
> end
>
>
> I've tried two different machines; The magic number of one is 4103 and
the
> other is 4175
>
> This is coincidentally close to a 4k buffer perhaps???

This happens on cygwin:

8187
8188
8189
8190
8191
8192
/usr/lib/ruby/1.8/yaml/rubytypes.rb:315:in `simple': failed to allocate
memory (
NoMemoryError)
        from /usr/lib/ruby/1.8/yaml/rubytypes.rb:315:in `to_yaml'
        from /usr/lib/ruby/1.8/yaml/rubytypes.rb:293:in `call'
        from /usr/lib/ruby/1.8/yaml.rb:188:in `quick_emit'
        from /usr/lib/ruby/1.8/yaml/rubytypes.rb:293:in `to_yaml'
        from /usr/lib/ruby/1.8/yaml/baseemitter.rb:175:in `map'
        from /usr/lib/ruby/1.8/yaml/baseemitter.rb:164:in `each'
        from /usr/lib/ruby/1.8/yaml/baseemitter.rb:164:in `map'
        from /usr/lib/ruby/1.8/yaml/rubytypes.rb:60:in `to_yaml'
        from /usr/lib/ruby/1.8/yaml/rubytypes.rb:55:in `call'
        from /usr/lib/ruby/1.8/yaml.rb:188:in `quick_emit'
        from /usr/lib/ruby/1.8/yaml/rubytypes.rb:55:in `to_yaml'
        from /usr/lib/ruby/1.8/yaml.rb:31:in `dump'
        from ./yaml-bug.rb:10

13:04:39 [ruby]: ruby -v
ruby 1.8.1 (2003-12-25) [i386-cygwin]


These behave identical (mem allocation error):

#!/bin/ruby

# hash created outside of loop

require 'yaml'

len = 1
a={}

while true
  a["test"] = 'x'*len
  puts len
  b = YAML.dump(a)
  len += 1
end


#!/bin/ruby

# only one string instance

require 'yaml'

str = ''

while true
  a = {"test"=>str}
  puts str.length
  b = YAML.dump(a)
  str << 'x'
end


#!/bin/ruby

# only 1 string and 1 Hash

require 'yaml'

str = ''
a = {}

while true
  a["test"]=str
  puts str.length
  b = YAML.dump(a)
  str << 'x'
end

Regards

    robert