MySQL error cannot load from Mysql.proc

Auth:jin

date:20140716

MySQL--default-character-set utf8-h127.0.0.1-uroot-p < account-20140716-1.sql
ERROR 1548 (HY000) at line 57:cannot load from Mysql.proc. The table is probably corrupted
mysql> SHOW PROCEDURE status;
ERROR 1548 (HY000): Cannot load from Mysql.proc. The table is probably corrupted
Mysql_upgrade-u root-p
Enter Password:
Looking for ' MySQL ' As:mysql
Looking for ' Mysqlcheck ' As:mysqlcheck
Running ' Mysqlcheck with default connection arguments
Running ' Mysqlcheck with default connection arguments

# mysql--default-character-set utf8-h127.0.0.1-uroot-p < account-20140716-1.sql
It's normal.

The

is said to be due to a field that was not successfully upgraded when the Mysql.proc was upgraded.
The comment field of the Mysql.proc table in 5.1 is varchar (+):
' comment ' char (UP) CHARACTER SET UTF8 COLLATE utf8_bin not NULL DEFAULT ' ',
But in 5.5 it should be text:
' comment ' text CHARACTER SET UTF8 COLLATE utf8_bin not NULL, so, execute the following statement, change this field to text, it is completely OK:
ALTER TABLE ' proc '
MODIFY COLUMN ' comment ' text CHARACTER SET UTF8 COLLATE utf8_bin not NULL after ' sql_mode ';