From: Run Paint Run Run <redmine@...>
Date: 2009-09-23T00:22:22+09:00
Subject: [ruby-core:25714] [Bug #2133] Segfault When Eval'ing Large Hash Literals

Bug #2133: Segfault When Eval'ing Large Hash Literals
http://redmine.ruby-lang.org/issues/show/2133

Author: Run Paint Run Run
Status: Open, Priority: Normal
Category: core, Target version: 1.9.2
ruby -v: ruby 1.9.2dev (2009-09-11) [i686-linux]

I can reproduce a segfault on ruby 1.9.2dev (2009-09-11) [i686-linux] by creating a hash with many thousands of keys, then eval'ing the result.

  $ cat /tmp/large-hash.rb
  hash = {}
  IO.foreach('/usr/share/dict/words') do |line|
    hash[line] = line.size
  end
  p "Hashed #{hash.keys.size} keys"
  eval <<EOF
  class C
    @@h = #{hash.inspect}
  end
  EOF

  $ ruby /tmp/large-hash.rb
  "Hashed 638311 keys"
  (eval):2: [BUG] Segmentation fault
  ruby 1.9.2dev (2009-09-11) [i686-linux]

  -- control frame ----------
  c:0007 p:261966 s:302922756 b:0017 l:000016 d:000016 CLASS  (eval):2
  c:0006 p:0009 s:0015 b:0015 l:00080c d:000014 EVAL   (eval):1
  c:0005 p:---- s:0013 b:0013 l:000012 d:000012 FINISH
  c:0004 p:---- s:0011 b:0011 l:000010 d:000010 CFUNC  :eval
  c:0003 p:0078 s:0007 b:0007 l:00080c d:000ea8 EVAL   /tmp/large-hash.rb:6
  c:0002 p:---- s:0004 b:0004 l:000003 d:000003 FINISH
  c:0001 p:0000 s:0002 b:0002 l:00080c d:00080c TOP   
  ---------------------------
  /tmp/large-hash.rb:6:in `<main>'
  /tmp/large-hash.rb:6:in `eval'
  (eval):1:in `<main>'
  (eval):2:in `<class:C>'

  -- C level backtrace information -------------------------------------------
  ruby(rb_vm_bugreport+0xb5) [0x8167535]
  ruby [0x81a3fcb]
  ruby(rb_bug+0x28) [0x81a4058]
  ruby [0x80fb585]
  [0xb7f29410]
  ruby [0x815e884]
  ruby [0x815f5c0]
  ruby(rb_f_eval+0xe1) [0x815fbd1]
  ruby [0x81537cd]
  ruby [0x8153919]
  ruby [0x8165555]
  ruby [0x81595fd]
  ruby [0x815e884]
  ruby(rb_iseq_eval_main+0x1a3) [0x815eb73]
  ruby(ruby_exec_node+0x97) [0x805d797]
  ruby(ruby_run_node+0x46) [0x805f0d6]
  ruby(main+0x60) [0x805cbb0]
  /lib/tls/i686/cmov/libc.so.6(__libc_start_main+0xe5) [0xb7d49775]
  ruby [0x805cab1]

  [NOTE]
  You may have encountered a bug in the Ruby interpreter or extension libraries.
  Bug reports are welcome.
  For details: http://www.ruby-lang.org/bugreport.html

(My dictionary is 6.5MB, so I haven't attached it.)

The same problem is encountered when the contents of the heredoc is piped to a file which is then require'd, also.

It is relevant that the hash is instantiated inside of a class; in the example below a segfault does not occur:
  
  $ cat /tmp/large-hash.rb
  hash = {}
  IO.foreach('/usr/share/dict/words') do |line|
    hash[line] = line.size
  end
  p "Hashed #{hash.keys.size} keys"
  eval "h = #{hash.inspect}"

  $ ruby /tmp/large-hash.rb
  "Hashed 638311 keys"
  (eval):0:in `<main>': stack level too deep (SystemStackError)
	from /tmp/large-hash.rb:6:in `eval'
	from /tmp/large-hash.rb:6:in `<main>'


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