LP #1614849: INFORMATION_SCHEMA.TABLES (or other schema info table) and GLOBAL_TEMPORARY_TABLES queries running in parallel may crash or hang

**Comment from Launchpad by: Laurynas Biveinis on: 25-08-2016 11:19:08

https://github.com/percona/percona-server/pull/870
https://github.com/percona/percona-server/pull/871
https://github.com/percona/percona-server/pull/872

**Comment from Launchpad by: Laurynas Biveinis on: 19-08-2016 06:51:41

First this was seen on 5.5 percona_show_temp_tables_stress, very intermittently, a TSan error:

==================
WARNING: ThreadSanitizer: data race (pid=12435)
Write of size 8 at 0x7d9c000000c0 by thread T26:
#0 Open_tables_state::set_open_tables_state(Open_tables_state*) /home/laurynas/mysql-server/sql/sql_class.h:1150 (mysqld+0x0000005b0b89)
#1 THD::restore_backup_open_tables_state(Open_tables_backup*) /home/laurynas/mysql-server/sql/sql_class.cc:3847 (mysqld+0x0000005b0b89)
#2 get_all_tables(THD*, TABLE_LIST*, Item*) /home/laurynas/mysql-server/sql/sql_show.cc:4582 (mysqld+0x0000006b56e8)
#3 do_fill_table /home/laurynas/mysql-server/sql/sql_show.cc:7666 (mysqld+0x0000006b63a1)
#4 get_schema_tables_result(JOIN*, enum_schema_table_state) /home/laurynas/mysql-server/sql/sql_show.cc:7773 (mysqld+0x0000006b63a1)
#5 JOIN::exec() /home/laurynas/mysql-server/sql/sql_select.cc:1977 (mysqld+0x000000684f3d)
#6 mysql_select(THD*, Item**, TABLE_LIST, unsigned int, List<Item>&, Item*, unsigned int, st_order*, st_order*, Item*, st_order*, unsigned long long, select_result*, st_select_lex_unit*, st_select_lex*) /home/laurynas/mysql-server/sql/sql_select.cc:2662 (mysqld+0x00000067d053)
#7 handle_select(THD*, LEX*, select_result*, unsigned long) /home/laurynas/mysql-server/sql/sql_select.cc:315 (mysqld+0x00000067d54a)
#8 execute_sqlcom_select /home/laurynas/mysql-server/sql/sql_parse.cc:4870 (mysqld+0x0000005f1fc1)
#9 mysql_execute_command(THD*) /home/laurynas/mysql-server/sql/sql_parse.cc:2363 (mysqld+0x0000005fdfec)
#10 sp_instr_stmt::exec_core(THD*, unsigned int*) /home/laurynas/mysql-server/sql/sp_head.cc:3222 (mysqld+0x0000009bbedc)
#11 sp_lex_keeper::reset_lex_and_exec_core(THD*, unsigned int*, bool, sp_instr*) /home/laurynas/mysql-server/sql/sp_head.cc:2991 (mysqld+0x0000009c8561)
#12 sp_instr_stmt::execute(THD*, unsigned int*) /home/laurynas/mysql-server/sql/sp_head.cc:3149 (mysqld+0x0000009c8973)
#13 sp_head::execute(THD*, bool) /home/laurynas/mysql-server/sql/sp_head.cc:1435 (mysqld+0x0000009c0c94)
#14 sp_head::execute_procedure(THD*, List<Item>*) /home/laurynas/mysql-server/sql/sp_head.cc:2192 (mysqld+0x0000009c3766)
#15 mysql_execute_command(THD*) /home/laurynas/mysql-server/sql/sql_parse.cc:4314 (mysqld+0x00000060791b)
#16 mysql_parse(THD*, char*, unsigned int, Parser_state*) /home/laurynas/mysql-server/sql/sql_parse.cc:6060 (mysqld+0x00000060aedb)
#17 dispatch_command(enum_server_command, THD*, char*, unsigned int) /home/laurynas/mysql-server/sql/sql_parse.cc:1075 (mysqld+0x00000060d689)
#18 do_command(THD*) /home/laurynas/mysql-server/sql/sql_parse.cc:789 (mysqld+0x000000610769)
#19 do_handle_one_connection(THD*) /home/laurynas/mysql-server/sql/sql_connect.cc:1418 (mysqld+0x00000075107d)
#20 handle_one_connection /home/laurynas/mysql-server/sql/sql_connect.cc:1325 (mysqld+0x00000075123e)
#21 pfs_spawn_thread /home/laurynas/mysql-server/storage/perfschema/pfs.cc:1015 (mysqld+0x000000a91eb4)
#22 <null> <null> (libtsan.so.0+0x0000000230d9)

Previous write of size 8 at 0x7d9c000000c0 by thread T25 (mutexes: write M604, write M96050, write M96049):
#0 safe_mutex_unlock /home/laurynas/mysql-server/mysys/thr_mutex.c:277 (mysqld+0x000000a70072)
#1 inline_mysql_mutex_unlock /home/laurynas/mysql-server/include/mysql/psi/mysql_thread.h:673 (mysqld+0x0000006a072f)
#2 fill_global_temporary_tables /home/laurynas/mysql-server/sql/sql_show.cc:4001 (mysqld+0x0000006a072f)
#3 do_fill_table /home/laurynas/mysql-server/sql/sql_show.cc:7666 (mysqld+0x0000006b63a1)
#4 get_schema_tables_result(JOIN*, enum_schema_table_state) /home/laurynas/mysql-server/sql/sql_show.cc:7773 (mysqld+0x0000006b63a1)
#5 JOIN::exec() /home/laurynas/mysql-server/sql/sql_select.cc:1977 (mysqld+0x000000684f3d)
#6 mysql_select(THD*, Item**, TABLE_LIST, unsigned int, List<Item>&, Item*, unsigned int, st_order*, st_order*, Item*, st_order*, unsigned long long, select_result*, st_select_lex_unit*, st_select_lex*) /home/laurynas/mysql-server/sql/sql_select.cc:2662 (mysqld+0x00000067d053)
#7 handle_select(THD*, LEX*, select_result*, unsigned long) /home/laurynas/mysql-server/sql/sql_select.cc:315 (mysqld+0x00000067d54a)
#8 execute_sqlcom_select /home/laurynas/mysql-server/sql/sql_parse.cc:4870 (mysqld+0x0000005f1fc1)
#9 mysql_execute_command(THD*) /home/laurynas/mysql-server/sql/sql_parse.cc:2363 (mysqld+0x0000005fdfec)
#10 sp_instr_stmt::exec_core(THD*, unsigned int*) /home/laurynas/mysql-server/sql/sp_head.cc:3222 (mysqld+0x0000009bbedc)
#11 sp_lex_keeper::reset_lex_and_exec_core(THD*, unsigned int*, bool, sp_instr*) /home/laurynas/mysql-server/sql/sp_head.cc:2991 (mysqld+0x0000009c8561)
#12 sp_instr_stmt::execute(THD*, unsigned int*) /home/laurynas/mysql-server/sql/sp_head.cc:3149 (mysqld+0x0000009c8973)
#13 sp_head::execute(THD*, bool) /home/laurynas/mysql-server/sql/sp_head.cc:1435 (mysqld+0x0000009c0c94)
#14 sp_head::execute_procedure(THD*, List<Item>*) /home/laurynas/mysql-server/sql/sp_head.cc:2192 (mysqld+0x0000009c3766)
#15 Event_job_data::execute(THD*, bool) /home/laurynas/mysql-server/sql/event_data_objects.cc:1434 (mysqld+0x000000726a3e)
#16 Event_worker_thread::run(THD*, Event_queue_element_for_exec*) /home/laurynas/mysql-server/sql/event_scheduler.cc:325 (mysqld+0x000000a23a55)
#17 event_worker_thread /home/laurynas/mysql-server/sql/event_scheduler.cc:282 (mysqld+0x000000a23c2f)
#18 pfs_spawn_thread /home/laurynas/mysql-server/storage/perfschema/pfs.cc:1015 (mysqld+0x000000a91eb4)
#19 <null> <null> (libtsan.so.0+0x0000000230d9)

**Comment from Launchpad by: Laurynas Biveinis on: 19-08-2016 06:49:51

This is caused by GLOBAL_TEMPORARY_TABLES query locking thd->LOCK_temporary_tables, TABLES query taking the backup of open tables state - which involves a bitwise copy of the mutex - and later restoring the copy, overwriting the mutex.