sort.c:

  Create block around DBUG_ENTER late in function

myisam/sort.c

@@ -322,8 +322,12 @@ pthread_handler_decl(thr_find_all_keys,arg)
 
   if (my_thread_init())
     goto err;
-  DBUG_ENTER("thr_find_all_keys");
-  DBUG_PRINT("enter", ("master: %d", sort_param->master));
+
+  { /* Expands to declaration, create new block */
+    DBUG_ENTER("thr_find_all_keys"); /* FIXME why no matching DBUG_RETURN ? */
+    DBUG_PRINT("enter", ("master: %d", sort_param->master));
+  }
+
   if (sort_param->sort_info->got_error)
     goto err;