Fix core dump in an endcase of b.strip() that I missed.
diff --git a/Lib/test/test_bytes.py b/Lib/test/test_bytes.py
index 094c56c..654cb86 100644
--- a/Lib/test/test_bytes.py
+++ b/Lib/test/test_bytes.py
@@ -653,6 +653,7 @@
         self.assertEqual(b.strip(b'pi'), b'mississ')
         self.assertEqual(b.strip(b'im'), b'ssissipp')
         self.assertEqual(b.strip(b'pim'), b'ssiss')
+        self.assertEqual(b.strip(b), b'')
 
     def test_lstrip(self):
         b = b'mississippi'
diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c
index 47ee8a4..b409a28 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -2502,7 +2502,10 @@
     argptr = ((PyBytesObject *)arg)->ob_bytes;
     argsize = Py_Size(arg);
     left = lstrip_helper(myptr, mysize, argptr, argsize);
-    right = rstrip_helper(myptr, mysize, argptr, argsize);
+    if (left == mysize)
+        right = left;
+    else
+        right = rstrip_helper(myptr, mysize, argptr, argsize);
     return PyBytes_FromStringAndSize(self->ob_bytes + left, right - left);
 }