Issue #7530 has been reported by headius (Charles Nutter).

----------------------------------------
Bug #7530: Concurrent loads fail with mutex errors
https://bugs.ruby-lang.org/issues/7530

Author: headius (Charles Nutter)
Status: Open
Priority: Normal
Assignee: 
Category: 
Target version: 
ruby -v: ruby 2.0.0dev (2012-12-01 trunk 38126) [x86_64-darwin11.4.2]


I have no idea what's going on here.

jruby-1.7.0 ~/projects/vts-jruby $ cat bench_load_path.rb 
require 'benchmark'

FAKE_PATHS = ARGV[0].to_i || 100
THREADS = 8
ITERATIONS_PER_THREAD = 1000

FAKE_PATHS.times do |i|
  $:.unshift "foo#{i}"
end

$: << '.'

system 'touch __load_path_bench_script__.rb'
puts Benchmark.measure {
  @threads = THREADS.times.map do
    Thread.new {
      ITERATIONS_PER_THREAD.times do
        require '__load_path_bench_script__'
        $".pop
      end
    }
  end
  @threads.each { |t| t.join }
}
system 'rm __load_path_bench_script__.rb'

jruby-1.7.0 ~/projects/vts-jruby $ ruby-2.0.0 -rubygems bench_load_path.rb 100
/usr/local/lib/ruby/2.0.0/rubygems/custom_require.rb:36:in `require': wrong argument type false (expected mutex) (TypeError)
	from /usr/local/lib/ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
	from bench_load_path.rb:18:in `block (4 levels) in <main>'
	from bench_load_path.rb:17:in `times'
	from bench_load_path.rb:17:in `block (3 levels) in <main>'

jruby-1.7.0 ~/projects/vts-jruby $ ruby-2.0.0 --disable-gems bench_load_path.rb 100
bench_load_path.rb:18:in `require': wrong argument type false (expected mutex) (TypeError)
	from bench_load_path.rb:18:in `block (4 levels) in <main>'
	from bench_load_path.rb:17:in `times'
	from bench_load_path.rb:17:in `block (3 levels) in <main>'

With verbose on, I get this error and a bunch of circular require warnings, even though I'm not doing any circular requires here.

ruby-2.0.0-preview2 ~/projects/vts-jruby $ ruby -v bench_load_path.rb 
ruby 2.0.0dev (2012-12-01 trunk 38126) [x86_64-darwin11.4.2]
/Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36: warning: loading in progress, circular require considered harmful - /Users/headius/projects/vts-jruby/__load_path_bench_script__.rb
	from bench_load_path.rb:17:in `block (3 levels) in <main>'
	from bench_load_path.rb:17:in `times'
	from bench_load_path.rb:18:in `block (4 levels) in <main>'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
/Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36: warning: loading in progress, circular require considered harmful - /Users/headius/projects/vts-jruby/__load_path_bench_script__.rb
	from bench_load_path.rb:17:in `block (3 levels) in <main>'
	from bench_load_path.rb:17:in `times'
	from bench_load_path.rb:18:in `block (4 levels) in <main>'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
/Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36: warning: loading in progress, circular require considered harmful - /Users/headius/projects/vts-jruby/__load_path_bench_script__.rb
	from bench_load_path.rb:17:in `block (3 levels) in <main>'
	from bench_load_path.rb:17:in `times'
	from bench_load_path.rb:18:in `block (4 levels) in <main>'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
/Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36: warning: loading in progress, circular require considered harmful - /Users/headius/projects/vts-jruby/__load_path_bench_script__.rb
	from bench_load_path.rb:17:in `block (3 levels) in <main>'
	from bench_load_path.rb:17:in `times'
	from bench_load_path.rb:18:in `block (4 levels) in <main>'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
/Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36: warning: loading in progress, circular require considered harmful - /Users/headius/projects/vts-jruby/__load_path_bench_script__.rb
	from bench_load_path.rb:17:in `block (3 levels) in <main>'
	from bench_load_path.rb:17:in `times'
	from bench_load_path.rb:18:in `block (4 levels) in <main>'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
/Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36: warning: loading in progress, circular require considered harmful - /Users/headius/projects/vts-jruby/__load_path_bench_script__.rb
	from bench_load_path.rb:17:in `block (3 levels) in <main>'
	from bench_load_path.rb:17:in `times'
	from bench_load_path.rb:18:in `block (4 levels) in <main>'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
/Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36: warning: loading in progress, circular require considered harmful - /Users/headius/projects/vts-jruby/__load_path_bench_script__.rb
	from bench_load_path.rb:17:in `block (3 levels) in <main>'
	from bench_load_path.rb:17:in `times'
	from bench_load_path.rb:18:in `block (4 levels) in <main>'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
/Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36: warning: loading in progress, circular require considered harmful - /Users/headius/projects/vts-jruby/__load_path_bench_script__.rb
	from bench_load_path.rb:17:in `block (3 levels) in <main>'
	from bench_load_path.rb:17:in `times'
	from bench_load_path.rb:18:in `block (4 levels) in <main>'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
/Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36: warning: loading in progress, circular require considered harmful - /Users/headius/projects/vts-jruby/__load_path_bench_script__.rb
	from bench_load_path.rb:17:in `block (3 levels) in <main>'
	from bench_load_path.rb:17:in `times'
	from bench_load_path.rb:18:in `block (4 levels) in <main>'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
/Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36: warning: loading in progress, circular require considered harmful - /Users/headius/projects/vts-jruby/__load_path_bench_script__.rb
	from bench_load_path.rb:17:in `block (3 levels) in <main>'
	from bench_load_path.rb:17:in `times'
	from bench_load_path.rb:18:in `block (4 levels) in <main>'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
/Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require': Attempt to unlock a mutex which is locked by another thread (ThreadError)
	from /Users/headius/.rvm/rubies/ruby-2.0.0-preview2/lib/ruby/site_ruby/2.0.0/rubygems/custom_require.rb:36:in `require'
	from bench_load_path.rb:18:in `block (4 levels) in <main>'
	from bench_load_path.rb:17:in `times'
	from bench_load_path.rb:17:in `block (3 levels) in <main>'


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