ha_innodb.cc:

  ha_innobase::create(): pass the query string as UTF-8
  to row_table_add_foreign_constraints()  (Bug #4649)

sql/ha_innodb.cc

@@ -3643,10 +3643,18 @@ ha_innobase::create(
 
 	if (current_thd->query != NULL) {
 
+		LEX_STRING q;
+		if (thd->convert_string(&q, system_charset_info,
+					current_thd->query,
+					current_thd->query_length,
+					current_thd->charset())) {
+			error = HA_ERR_OUT_OF_MEM;
+		} else {
 			error = row_table_add_foreign_constraints(trx,
-					current_thd->query, norm_name);
+					q.str, norm_name);
 
 			error = convert_error_code_to_mysql(error, NULL);
+		}
 
 		if (error) {
 			innobase_commit_low(trx);