Index: Lib/io.py
===================================================================
--- Lib/io.py	(révision 65930)
+++ Lib/io.py	(copie de travail)
@@ -61,7 +61,7 @@
 import _fileio
 # Import _thread instead of threading to reduce startup cost
 try:
-    from _thread import allocate_lock as Lock
+    from _thread import RLock as Lock
 except ImportError:
     from _dummy_thread import allocate_lock as Lock
 
Index: Lib/test/test_io.py
===================================================================
--- Lib/test/test_io.py	(révision 65930)
+++ Lib/test/test_io.py	(copie de travail)
@@ -1237,6 +1237,20 @@
             else:
                 self.assert_(issubclass(obj, io.IOBase))
 
+    def testIssue3618(self):
+        # deadlock in BufferedRandom.write() when using an hook in ceval
+        # (eg. using a profiler)
+        import _lsprof
+        stream = io.BufferedWriter(io.StringIO())
+        def invalidTimestamp():
+            stream.write(b"in the profiler\n")
+            return 1
+        profiler = _lsprof.Profiler(invalidTimestamp)
+        try:
+            profiler.enable()
+            stream.write(b"test deadlock\n")
+        finally:
+            profiler.disable()
 
 def test_main():
     support.run_unittest(IOTest, BytesIOTest, StringIOTest,