Index: Modules/mmapmodule.c
===================================================================
--- Modules/mmapmodule.c	(revision 87957)
+++ Modules/mmapmodule.c	(working copy)
@@ -163,8 +163,6 @@
 #endif /* MS_WINDOWS */
 
 #ifdef UNIX
-    if (0 <= self->fd)
-        (void) close(self->fd);
     self->fd = -1;
     if (self->data != NULL) {
         munmap(self->data, self->size);
@@ -1150,12 +1148,7 @@
         }
 #endif
     } else {
-        m_obj->fd = dup(fd);
-        if (m_obj->fd == -1) {
-            Py_DECREF(m_obj);
-            PyErr_SetFromErrno(mmap_module_error);
-            return NULL;
-        }
+        m_obj->fd = fd;
     }
 
     m_obj->data = mmap(NULL, map_size,