--- python-2.7.2/Modules/mmapmodule.c  2011-06-12 00:46:27.000000000 +0900
+++ python-2.7.2/Modules/mmapmodule.c  2011-10-11 08:50:01.617040950 +0900
@@ -1188,7 +1188,7 @@
 #  endif
     if (fd != -1 && fstat(fd, &st) == 0 && S_ISREG(st.st_mode)) {
         if (map_size == 0) {
-            if (offset >= st.st_size) {
+            if (offset > st.st_size) {
                 PyErr_SetString(PyExc_ValueError,
                                 "mmap offset is greater than file size");
                 return NULL;