Merge pull request #7714 from devreal/opal-progress-unregister-oob

Fix potential out-of-bounds write in opal_progress_unregister

opal/runtime/opal_progress.c

@@ -474,8 +474,8 @@ static int _opal_progress_unregister (opal_progress_callback_t cb, volatile opal
         (void) opal_atomic_swap_ptr ((opal_atomic_intptr_t *) (callback_array + i), (intptr_t) callback_array[i+1]);
     }
 
-    callback_array[*callback_array_len] = fake_cb;
     --*callback_array_len;
+    callback_array[*callback_array_len] = fake_cb;
 
     return OPAL_SUCCESS;
 }