SHOW_ROUTINE_GRANTS | SQL/SQL_ACL.CC:6873

Description:- Renaming the "mysql.procs_priv" table and
executing SHOW GRANTS results in a server crash.

Analysis:- After renaming the "mysql.procs_priv" table, even
though FLUSH PRIVILEGES will throw an error "ERROR 1146
(42S02): Table 'mysql.procs_priv' doesn't exist",
"grant_reload_procs_priv()" is not freeing the existing
"proc_priv_hash" and "func_priv_hash" structures. This
results in a server crash while executing SHOW GRANTS. The
server crash is due to the invalid memory access in
"mysql_show_grants()", which occurs because of the freeing
of MEM_ROOT in "grant_reload()" as a part of loading the
"table_priv" and "columns_priv" structures. Due to this,
"mysql_show_grants()" is unable to use old values.

Fix:- In "grant_reload_procs_priv()", "proc_priv_hash" and
"func_priv_hash" structure are freed if
open_and_lock_tables()" fails for 'mysql.procs_priv'
table". This same behaviour is done for "mysql.user",
"mysql.db", "mysql.proxies_priv", "mysql.tables_priv" and
"mysql.columns_priv" tables. If "open_and_lock_tables()"
fails for any of these tables, then the correspoding
structures are freed.