Added 'NULL' checks to avoid accessing 'GloMTH' in 'push_MyConn_to_pool' after being freed

lib/MySQL_HostGroups_Manager.cpp

@@ -2671,6 +2671,7 @@ void MySQL_HostGroups_Manager::push_MyConn_to_pool(MySQL_Connection *c, bool _lo
 	mysrvc=(MySrvC *)c->parent;
 	proxy_debug(PROXY_DEBUG_MYSQL_CONNPOOL, 7, "Returning MySQL_Connection %p, server %s:%d with status %d\n", c, mysrvc->address, mysrvc->port, mysrvc->status);
 	mysrvc->ConnectionsUsed->remove(c);
+	if (GloMTH == NULL) { goto __exit_push_MyConn_to_pool; }
 	if (c->largest_query_length > (unsigned int)GloMTH->variables.threshold_query_length) {
 		proxy_debug(PROXY_DEBUG_MYSQL_CONNPOOL, 7, "Destroying MySQL_Connection %p, server %s:%d with status %d . largest_query_length = %lu\n", c, mysrvc->address, mysrvc->port, mysrvc->status, c->largest_query_length);
 		delete c;
@@ -2678,6 +2679,7 @@ void MySQL_HostGroups_Manager::push_MyConn_to_pool(MySQL_Connection *c, bool _lo
 	}
 	if (mysrvc->status==MYSQL_SERVER_STATUS_ONLINE) {
 		if (c->async_state_machine==ASYNC_IDLE) {
+			if (GloMTH == NULL) { goto __exit_push_MyConn_to_pool; }
 			if (c->local_stmts->get_num_backend_stmts() > (unsigned int)GloMTH->variables.max_stmts_per_connection) {
 				proxy_debug(PROXY_DEBUG_MYSQL_CONNPOOL, 7, "Destroying MySQL_Connection %p, server %s:%d with status %d because has too many prepared statements\n", c, mysrvc->address, mysrvc->port, mysrvc->status);
 //				delete c;