An object with __call__ as an attribute, when called, will have that attribute checked for __call__ itself, and will continue to look until it finds an object without the attribute.  This can lead to an infinite recursion.

Closes bug #532646, again.  Will be backported.
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
index ca91042..d9249b6 100644
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -3171,6 +3171,21 @@
     list.__init__(a, sequence=[0, 1, 2])
     vereq(a, [0, 1, 2])
 
+def recursive__call__():
+    if verbose: print ("Testing recursive __call__() by setting to instance of "
+                        "class ...")
+    class A(object):
+        pass
+
+    A.__call__ = A()
+    try:
+        A()()
+    except RuntimeError:
+        pass
+    else:
+        raise TestFailed("Recursion limit should have been reached for "
+                         "__call__()")
+
 def delhook():
     if verbose: print "Testing __del__ hook..."
     log = []
@@ -4164,6 +4179,7 @@
     buffer_inherit()
     str_of_str_subclass()
     kwdargs()
+    recursive__call__()
     delhook()
     hashinherit()
     strops()