diff --git a/plugin/business/traffic-mirror/src/entry.cpp b/plugin/business/traffic-mirror/src/entry.cpp
index 6943df5..85b46ed 100644
--- a/plugin/business/traffic-mirror/src/entry.cpp
+++ b/plugin/business/traffic-mirror/src/entry.cpp
@@ -25,8 +25,15 @@ void policy_table_ex_data_dup_cb(int table_id, MAAT_PLUGIN_EX_DATA * to,
     MAAT_PLUGIN_EX_DATA * from, long argl, void * argp)
 {
     struct policy_table_ex_data * ex_data = (struct policy_table_ex_data *)*from;
-    __sync_add_and_fetch(&ex_data->atomic_refcnt, 1);
-    *to = (void *)ex_data;
+	if(ex_data==NULL)
+	{
+		*to=NULL;
+	}
+	else
+	{
+    	__sync_add_and_fetch(&ex_data->atomic_refcnt, 1);
+	    *to = (void *)ex_data;
+	}
 }
 
 void policy_table_ex_data_free_cb(int table_id, MAAT_PLUGIN_EX_DATA * ad, long argl, void * argp)