Bug #100283 Super_read_only prevents myisam_recover_options from working

Description:
When the following is set on startup:

super_read_only=ON
myisam_recover_options=BACKUP,FORCE

and MyISAM table is crashed. myisam_recover_options will not work and start up fails. Removing super_read_only=ON allows myisam_recover_options to work and repair crashed myisam tables.

Affects MySQL v5.7.31

How to repeat:
In my.cnf:
super_read_only=ON
myisam_recover_options=BACKUP,FORCE

T1 - run
set @@global.super_read_only=OFF; <-- execute from mysql client connection
while ; do mysql -uroot -e “create user ‘mytest’@‘localhost’ identified by ‘mypass’; grant all privileges on . to ‘mytest’@‘localhost’; flush privileges;”; sleep 1; mysql -uroot -e “drop user ‘mytest’@‘localhost’;”; done;

T2 - kill -11 $(pgrep mysqld)
This would crash mysqld causing mysql.user table myisam table to be on crashed state.

Startup would fail with this error:
2020-07-22T07:29:34.981978Z 0 [Note] Server socket created on IP: '::'.
2020-07-22T07:29:34.989095Z 0 [ERROR] /usr/sbin/mysqld: Table './mysql/user' is marked as crashed and should be repaired
2020-07-22T07:29:34.989193Z 0 [ERROR] Fatal error: Can't open and lock privilege tables: Table './mysql/user' is marked as crashed and should be repaired
2020-07-22T07:29:34.989315Z 0 [ERROR] Fatal error: Failed to initialize ACL/grant/time zones structures or failed to remove temporary table files.
2020-07-22T07:29:34.989501Z 0 [ERROR] Aborting

This will be an endless startup loop

Edit my.cnf to comment out super_read_only=ON afterwhich startup works and myisam_recover_options will then kick in:
2020-07-22T07:29:38.735818Z 0 [ERROR] /usr/sbin/mysqld: Table './mysql/user' is marked as crashed and should be repaired
2020-07-22T07:29:38.736274Z 0 [Warning] Checking table:   './mysql/user'
2020-07-22T07:29:38.736398Z 0 [ERROR] 1 client is using or hasn't closed the table properly
2020-07-22T07:29:38.752046Z 0 [Note] Event Scheduler: Loaded 0 events
2020-07-22T07:29:38.752390Z 0 [Note] /usr/sbin/mysqld: ready for connections.
Version: '5.7.31'  socket: '/var/lib/mysql/mysql.sock'  port: 3306  MySQL Community Server (GPL)

Suggested fix:
Do not block myisam_recover_options if super_read_only is enabled.

Maybe fix on https://bugs.mysql.com/bug.php?id=91852 affected some code related to this.

Hello Jericho,

Thank you for the report and test case.
Verified as described with 5.7.31 build.

regards,
Umesh