diff --git a/src/entry/Maat_api.cpp b/src/entry/Maat_api.cpp
index 2ae109d..fdff783 100644
--- a/src/entry/Maat_api.cpp
+++ b/src/entry/Maat_api.cpp
@@ -235,6 +235,7 @@ int region_compile(_Maat_feather_t*feather, struct Maat_hierarchy_compile_mid* c
 	for(i=0; (size_t)i<region_hit_num;i++)
 	{
 		region=*(struct Maat_region_inner**)((char*)region_hit+region_type_size*i+user_data_offset);
+		assert(region->magic_num==REGION_RULE_MAGIC);
 		if(region_hit_wraper->virtual_table_ids)
 		{
 			virtual_table_id=region_hit_wraper->virtual_table_ids[i];
diff --git a/src/entry/Maat_hierarchy.cpp b/src/entry/Maat_hierarchy.cpp
index ca14f55..b97f50f 100644
--- a/src/entry/Maat_hierarchy.cpp
+++ b/src/entry/Maat_hierarchy.cpp
@@ -1052,6 +1052,12 @@ void Maat_hierarchy_compile_mid_udpate(struct Maat_hierarchy_compile_mid* mid, i
 	mid->this_scan_region_hit_cnt++;
 	pthread_rwlock_rdlock(&hier->rwlock);
 	HASH_FIND_INT(hier->hash_region_by_id, &region_id, region);
+	if(!region)
+	{
+		pthread_rwlock_unlock(&hier->rwlock);
+		return;
+	}
+	
 	group=region->ref_parent_group;
 	
 	if(group->top_group_cnt==0)
diff --git a/src/entry/Maat_rule.cpp b/src/entry/Maat_rule.cpp
index 413f89e..6a944fc 100644
--- a/src/entry/Maat_rule.cpp
+++ b/src/entry/Maat_rule.cpp
@@ -34,7 +34,7 @@
 #include "stream_fuzzy_hash.h"
 #include "gram_index_engine.h"
 
-int MAAT_FRAME_VERSION_3_0_20200703=1;
+int MAAT_FRAME_VERSION_3_0_20200706=1;
 
 int is_valid_table_name(const char* str)
 {
@@ -715,6 +715,8 @@ void op_expr_add_rule(struct op_expr_t* op_expr,scan_rule_t* p_rule)
 }
 void Maat_region_inner_free(struct Maat_region_inner* region)
 {
+	assert(region->magic_num==REGION_RULE_MAGIC);
+	region->magic_num=0;
 	free(region);
 }
 
@@ -1031,6 +1033,7 @@ int get_district_id(Maat_scanner *scanner,const char* district_str)
 struct Maat_region_inner* Maat_region_inner_new(int group_id, int region_id, int table_id, int district_id)
 {
 	struct Maat_region_inner* region=ALLOC(struct Maat_region_inner, 1);
+	region->magic_num=REGION_RULE_MAGIC;
 	region->region_id=region_id;
 	region->group_id=group_id;
 	region->table_id=table_id;
diff --git a/src/inc_internal/Maat_rule_internal.h b/src/inc_internal/Maat_rule_internal.h
index 74c3690..c016ff0 100644
--- a/src/inc_internal/Maat_rule_internal.h
+++ b/src/inc_internal/Maat_rule_internal.h
@@ -136,9 +136,10 @@ struct op_expr_t
 	int table_id;
 	int rule_type;
 };
-
+#define	REGION_RULE_MAGIC	0x4d3c2b1a
 struct Maat_region_inner
 {
+	long long magic_num;
 	int region_id;
 	int group_id;
 	int district_id;