Bug #7530: Concurrent loads fail with mutex errors

• Status: Closed
• Assignee: Glass_saga (Masaki Matsushita)
• Target version: -
• ruby -v: ruby 2.0.0dev (2012-12-01 trunk 38126) [x86_64-darwin11.4.2]

[headius (Charles Nutter)]

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>'

[usa (Usaku NAKAMURA)]

• Category set to core
• Status changed from Open to Assigned
• Assignee set to kosaki (Motohiro KOSAKI)
• Target version set to 2.0.0

[kosaki (Motohiro KOSAKI)]

• Assignee changed from kosaki (Motohiro KOSAKI) to nobu (Nobuyoshi Nakada)

When removing $".pop likes following, this issue never happen.
So, I suspect this is require and threadshield issue.

---

require 'benchmark'

FAKE_PATHS = ARGV[0].to_i || 100
THREADS = 2
ITERATIONS_PER_THREAD = 1000

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

$: << '.'

ITERATIONS_PER_THREAD.times {|i|
  system "touch __load_path_bench_script__#{i}.rb"
}

puts Benchmark.measure {
  @threads = THREADS.times.map do
    Thread.new {
      ITERATIONS_PER_THREAD.times do |i|
        require "__load_path_bench_script__#{i}"
      end
    }
  end
  @threads.each { |t| t.join }
}

ITERATIONS_PER_THREAD.times {|i|
  system "rm __load_path_bench_script__#{i}.rb"
}

[nobu (Nobuyoshi Nakada)]

• Priority changed from Normal to 5

[Glass_saga (Masaki Matsushita)]

Here is the minimal code:

THREADS = 2
ITERATIONS_PER_THREAD = 1000

system 'touch __load_path_bench_script__.rb'
THREADS.times.map {
  Thread.new do
    ITERATIONS_PER_THREAD.times do
      require_relative '__load_path_bench_script__'
      $".pop
    end
  end
}.each(&:join)
system 'rm __load_path_bench_script__.rb'

[Glass_saga (Masaki Matsushita)]

• Assignee changed from nobu (Nobuyoshi Nakada) to Glass_saga (Masaki Matsushita)

• Status changed from Assigned to Closed
• % Done changed from 0 to 100

This issue was solved with changeset r38744.
Charles, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.

---

• load.c (load_lock): fix not to delete thread shield twice.
  it may break the shield locked by another thread.
  [Bug #7530] [ruby-core:50645]

• test/ruby/test_require.rb: a test for above.

[nobu (Nobuyoshi Nakada)]

• Related to Bug #10892: Deadlock in autoload added

[nobu (Nobuyoshi Nakada)]

• Description updated (diff)

[shugo (Shugo Maeda)]

• Related to Bug #12999: there still exist race conditions in require added