Description:
The server will crash if there is a trigger on mysql.user and a CREATE or DROP USER or any GRANT/REVOKE statement is issued.
How to repeat:
create user 'myuser';
create table test.t1 (user varchar(16));
create trigger `testtrig` after insert on mysql.user for each row insert into test.t1 values (new.user);
create user 'tester';
drop user 'myuser';
mysql 5.0.20-max-log (root) [mysql]> create user 'myuser';
Query OK, 0 rows affected (0.02 sec)
mysql 5.0.20-max-log (root) [mysql]> create table test.t1 (user varchar(16));
Query OK, 0 rows affected (0.02 sec)
mysql 5.0.20-max-log (root) [mysql]> create trigger `testtrig` after insert on mysql.user for each row insert into test.t1 values (new.user);
Query OK, 0 rows affected (0.00 sec)
mysql 5.0.20-max-log (root) [mysql]> create user 'tester';
ERROR 2013 (HY000): Lost connection to MySQL server during query
mysql 5.0.20-max-log (root) [mysql]>
Number of processes running now: 0
060424 13:14:24 mysqld restarted
mysql 5.0.20-max-log (root) [mysql]> drop user 'myuser';
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id: 1
Current database: mysql
ERROR 2013 (HY000): Lost connection to MySQL server during query
mysql 5.0.20-max-log (root) [mysql]>
Number of processes running now: 0
060424 13:14:40 mysqld restarted
mysql 5.0.20-max-log (root) [mysql]> drop user 'nonexistent';
ERROR 2006 (HY000): MySQL server has gone away
No connection. Trying to reconnect...
Connection id: 1
Current database: mysql
ERROR 2013 (HY000): Lost connection to MySQL server during query
mysql 5.0.20-max-log (root) [mysql]>
Number of processes running now: 0
060424 13:15:23 mysqld restarted
0x818e082 handle_segfault + 426
0xffffe500 _end + -141827080
0x8209727 open_grant_tables__FP3THDP13st_table_list + 447
0x8209727 open_grant_tables__FP3THDP13st_table_list + 447
0x820a1a8 mysql_create_user__FP3THDRt4List1Z11st_lex_user + 112
0x81a2a7a mysql_execute_command__FP3THD + 12022
0x81a6c38 mysql_parse__FP3THDPcUi + 288
0x819e646 dispatch_command__F19enum_server_commandP3THDPcUi + 1894
0x819ded3 do_command__FP3THD + 195
0x819d414 handle_one_connection + 764
0x555a0927 _end + 1290143775
0x556d0e8e _end + 1291390342
Suggested fix:
Obvious.