io.c: get rid of race condition

* io.c (rb_io_close_write): detach tied IO for writing before closing
  to get rid of race condition.  [ruby-list:49598]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@43114 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,4 +1,7 @@
-Wed Oct  2 14:18:56 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+Wed Oct  2 14:19:57 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* io.c (rb_io_close_write): detach tied IO for writing before closing
+	  to get rid of race condition.  [ruby-list:49598]
 
 	* io.c (rb_io_close_read): keep fptr in write_io to be discarded, to
 	  fix freed pointer access when it is in use by other threads, and get

io.c

@@ -4492,12 +4492,12 @@ rb_io_close_write(VALUE io)
 	rb_raise(rb_eIOError, "closing non-duplex IO for writing");
     }
 
-    rb_io_close(write_io);
     if (io != write_io) {
 	GetOpenFile(io, fptr);
 	fptr->tied_io_for_writing = 0;
 	fptr->mode &= ~FMODE_DUPLEX;
     }
+    rb_io_close(write_io);
     return Qnil;
 }
 

test/ruby/test_io.rb

@@ -1380,6 +1380,19 @@ class TestIO < Test::Unit::TestCase
     end
   end
 
+  def test_close_read_write_separately
+    bug = '[ruby-list:49598]'
+    (1..10).each do |i|
+      assert_nothing_raised(IOError, "#{bug} trying ##{i}") do
+        IO.popen(EnvUtil.rubybin, "r+") {|f|
+          th = Thread.new {f.close_write}
+          f.close_read
+          th.join
+        }
+      end
+    end
+  end
+
   def test_pid
     r, w = IO.pipe
     assert_equal(nil, r.pid)