1 files changed, 63 insertions, 0 deletions
diff --git a/test/ruby/test_thread.rb b/test/ruby/test_thread.rb
index 12ba1165ed..2a61fc3450 100644
--- a/test/ruby/test_thread.rb
+++ b/test/ruby/test_thread.rb
@@ -1480,6 +1480,8 @@ q.pop
   end
 
   def test_thread_interrupt_for_killed_thread
+    pend "hang-up" if /mswin|mingw/ =~ RUBY_PLATFORM
+
     opts = { timeout: 5, timeout_error: nil }
 
     assert_normal_exit(<<-_end, '[Bug #8996]', **opts)
@@ -1589,4 +1591,65 @@ q.pop
       frame_for_deadlock_test_2 { t.join }
     INPUT
   end
+
+  # [Bug #21342]
+  def test_unlock_locked_mutex_with_collected_fiber
+    bug21127 = '[ruby-core:120930] [Bug #21127]'
+    assert_ruby_status([], "#{<<~"begin;"}\n#{<<~'end;'}")
+    begin;
+      5.times do
+        m = Mutex.new
+        Thread.new do
+          m.synchronize do
+          end
+        end.join
+        Fiber.new do
+          GC.start
+          m.lock
+        end.resume
+      end
+    end;
+  end
+
+  def test_unlock_locked_mutex_with_collected_fiber2
+    assert_ruby_status([], "#{<<~"begin;"}\n#{<<~'end;'}")
+    begin;
+      MUTEXES = []
+      5.times do
+        m = Mutex.new
+        Fiber.new do
+          GC.start
+          m.lock
+        end.resume
+        MUTEXES << m
+      end
+      10.times do
+        MUTEXES.clear
+        GC.start
+      end
+    end;
+  end
+
+  def test_mutexes_locked_in_fiber_dont_have_aba_issue_with_new_fibers
+    assert_ruby_status([], "#{<<~"begin;"}\n#{<<~'end;'}")
+    begin;
+      mutexes = 1000.times.map do
+        Mutex.new
+      end
+
+      mutexes.map do |m|
+        Fiber.new do
+          m.lock
+        end.resume
+      end
+
+      GC.start
+
+      1000.times.map do
+        Fiber.new do
+          raise "FAILED!" if mutexes.any?(&:owned?)
+        end.resume
+      end
+    end;
+  end
 end