[auto parallel] bug fix for op has sub_block attr created with copy_from (#44664)

python/paddle/distributed/auto_parallel/partitioner.py

@@ -179,6 +179,16 @@ class Partitioner(object):
 
         partitioned_main_prog.current_block_idx = 0
 
+        # should reconnect the block_attr ptr to the correct block
+        for block_id in range(self._dist_context.block_state.nblock):
+            block = partitioned_main_prog.block(block_id)
+            for op in block.ops:
+                for attr_name in op.all_attrs():
+                    if op.attr_type(attr_name) == core.AttrType.BLOCK:
+                        relative_id = op._block_attr_id(attr_name)
+                        op._set_attr(attr_name,
+                                     partitioned_main_prog.block(relative_id))
+
         partitioned_params_and_grads = []
         for p, g in params_and_grads:
             assert p.name in self._serial2dist_varname_mapping