From: "vjoel (Joel VanderWerf)" <vjoel@...>
Date: 2013-05-07T14:43:10+09:00
Subject: [ruby-core:54842] [ruby-trunk - Bug #8374][Open] race condition when two threads require a gem with a C extension


Issue #8374 has been reported by vjoel (Joel VanderWerf).

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Bug #8374: race condition when two threads require a gem with a C extension
https://bugs.ruby-lang.org/issues/8374

Author: vjoel (Joel VanderWerf)
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 
ruby -v: ruby 2.0.0p0 (2013-02-24) [i686-linux]
Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN


Requiring a gem with a C extension seems to be not threadsafe.
  
Any one of the require lines below will frequently (but not always) cause an error like the following:
  
      /usr/local/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:45:in `require': cannot load such file -- sqlite3 (LoadError)
	      from /usr/local/lib/ruby/site_ruby/2.0.0/rubygems/core_ext/kernel_require.rb:45:in `require'
	      from thread.rb:7:in `block (2 levels) in <main>'
  
Using one thread avoids the problem.

__BEGIN__

ths = (1..2).map do
  Thread.new do
#    require 'msgpack'
#    require 'yajl'
#    require 'sequel'
#    require 'nio4r'
    require 'sqlite3'
  end
end

ths.each {|th| th.join}



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