diff -r 95d09ba14aa7 Lib/test/pickletester.py
--- a/Lib/test/pickletester.py	Wed Apr 15 18:34:17 2015 -0400
+++ b/Lib/test/pickletester.py	Thu Apr 16 08:51:31 2015 -0500
@@ -906,7 +906,6 @@
             y = self.loads(s)
             self.assertEqual(y._proto, proto)
 
-    @unittest.skip("FIXME: max recursion")
     def test_reduce_calls_base(self):
         for proto in protocols:
             x = REX_five()
@@ -1093,7 +1092,6 @@
         self.module.Pickler(f, -1)
         self.module.Pickler(f, protocol=-1)
 
-    @unittest.skip("FIXME: not working.")
     def test_incomplete_input(self):
         s = StringIO.StringIO("X''.")
         self.assertRaises(EOFError, self.module.load, s)
@@ -1108,7 +1106,6 @@
         exec teststr in {'__builtins__': builtins}, d
         d['f']()
 
-    @unittest.skip("FIXME: not working.")
     def test_bad_input(self):
         # Test issue4298
         s = '\x58\0\0\0\x54'
diff -r 95d09ba14aa7 src/org/python/core/PyObject.java
--- a/src/org/python/core/PyObject.java	Wed Apr 15 18:34:17 2015 -0400
+++ b/src/org/python/core/PyObject.java	Thu Apr 16 08:51:31 2015 -0500
@@ -125,7 +125,7 @@
             throw Py.TypeError(String.format("Can't instantiate abstract class %s with abstract "
                                              + "methods %s", subtype.fastGetName(), methods));
         }
-        
+
         return new_.for_type == subtype ? new PyObject() : new PyObjectDerived(subtype);
     }
 
@@ -3950,6 +3950,25 @@
     }
 
     /**
+     * A common helper method, use to prevent infinite recursion
+     * when a Python object implements __reduce__ and sometimes calls
+     * object.__reduce__. Trying to do it all in __reduce__ex__ caused
+     # this problem. See http://bugs.jython.org/issue2323.
+     */
+    private PyObject commonReduce(int proto) {
+        PyObject res;
+
+        if (proto >= 2) {
+            res = reduce_2();
+        } else {
+            PyObject copyreg = __builtin__.__import__("copy_reg", null, null, Py.EmptyTuple);
+            PyObject copyreg_reduce = copyreg.__findattr__("_reduce_ex");
+            res = copyreg_reduce.__call__(this, new PyInteger(proto));
+        }
+        return res;
+    }
+
+    /**
      * Used for pickling.  Default implementation calls object___reduce__.
      *
      * @return a tuple of (class, tuple)
@@ -3960,7 +3979,7 @@
 
     @ExposedMethod(doc = BuiltinDocs.object___reduce___doc)
     final PyObject object___reduce__() {
-        return object___reduce_ex__(0);
+        return commonReduce(0);
     }
 
     /** Used for pickling.  If the subclass specifies __reduce__, it will
@@ -3987,12 +4006,8 @@
 
         if (clsreduce != objreduce) {
             res = this.__reduce__();
-        } else if (arg >= 2) {
-            res = reduce_2();
         } else {
-            PyObject copyreg = __builtin__.__import__("copy_reg", null, null, Py.EmptyTuple);
-            PyObject copyreg_reduce = copyreg.__findattr__("_reduce_ex");
-            res = copyreg_reduce.__call__(this, new PyInteger(arg));
+            res = commonReduce(arg);
         }
         return res;
     }
diff -r 95d09ba14aa7 src/org/python/modules/cPickle.java
--- a/src/org/python/modules/cPickle.java	Wed Apr 15 18:34:17 2015 -0400
+++ b/src/org/python/modules/cPickle.java	Thu Apr 16 08:51:31 2015 -0500
@@ -610,7 +610,6 @@
         return dumps(object, 0);
     }
 
-
     /**
      * Shorthand function which pickles and returns the string representation.
      * @param object    a data object which should be pickled.
@@ -623,7 +622,6 @@
         return file.getvalue();
     }
 
-
     /**
      * Shorthand function which unpickles a object from the file and returns
      * the new object.
@@ -633,7 +631,16 @@
      * @return         a new object.
      */
     public static Object load(PyObject file) {
-        return new Unpickler(file).load();
+        try {
+            return new Unpickler(file).load();
+        }
+        catch (ArrayIndexOutOfBoundsException e) {
+            // invalid data, bad stack
+            throw Py.IndexError(e.getMessage());
+        } catch (StringIndexOutOfBoundsException e) {
+            // short data
+            throw Py.EOFError(e.getMessage());
+        }
     }
 
 
@@ -646,13 +653,13 @@
      */
     public static Object loads(PyObject str) {
         cStringIO.StringIO file = cStringIO.StringIO(str.toString());
-        return new Unpickler(file).load();
+        return load(file);
     }
 
 
 
     // Factory for creating PyIOFile representation.
-    
+
     /**
      * The Pickler object
      * @see cPickle#Pickler(PyObject)