Mysql事务问题求指教（在线等）?报错

现有两存储过程A,B

CREATE DEFINER=`root`@`%` PROCEDURE `A`()
_return:BEGIN
DECLARE _error INT DEFAULT 0; #异常标记
DECLARE CONTINUE HANDLER FOR SQLEXCEPTION SET _error = 1; #sqlexception返回值
 
START TRANSACTION; #开启事务
  
CALL B();#调用另一个存储过程
IF @ret < 0 THEN
ROLLBACK; 
LEAVE _return;
END IF;
 
IF _error <> 0 THEN
ROLLBACK; 
LEAVE _return;
ELSE 
COMMIT;#提交事务
END IF;
END$$

CREATE DEFINER=`root`@`%` PROCEDURE `B`()
_return:BEGIN
DECLARE _error INT DEFAULT 0; #异常标记
 
DECLARE CONTINUE HANDLER FOR SQLEXCEPTION SET _error = 1;
SET out_ret = -1;
SET out_desc = '执行失败';
SET @ret = -2;
SET @ret_desc = '校验失败';
###############################这里是一些DML语句
IF _error <> 0 THEN 
ROLLBACK;
SET out_ret = -3;
SET out_desc = '执行异常';
LEAVE _return; 
ELSE 
SET out_ret = 1;
SET out_desc = '';
  END IF;
END$$
附上存储过程B的图片：