drop table if exists `t1`;
create table `t1`(`a` char(1) character set utf8)engine=innodb;
select 1 from `t1` where `a` in (select group_concat(`a`) from t1);


Version: '10.0.0-MariaDB'  socket: 'sock'  port: 3306  MariaDB Server
--785-- REDIR: 0x367989ceb0 (strstr) redirected to 0x48016fe (_vgnU_ifunc_wrapper)
--785-- REDIR: 0x367989ca40 (__GI_strstr) redirected to 0x4a0bbb0 (strstr)
==785== Thread 22:
==785== Conditional jump or move depends on uninitialised value(s)
==785==    at 0x713CAE: Item_cond::fix_fields(THD*, Item**) (item_cmpfunc.cc:4266)
==785==    by 0x67B982: setup_jtbm_semi_joins(JOIN*, List<TABLE_LIST>*, Item**) (opt_subselect.cc:5230)
==785==    by 0x5CB6C7: JOIN::optimize_inner() (sql_select.cc:1123)
==785==    by 0x5D573E: 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*) (sql_select.cc:985)
==785==    by 0x5D6411: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:362)
==785==    by 0x581957: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:4937)
==785==    by 0x584659: mysql_execute_command(THD*) (sql_parse.cc:2421)
==785==    by 0x58B4C8: mysql_parse(THD*, char*, unsigned int, Parser_state*) (sql_parse.cc:6056)
==785==    by 0x58CC74: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1216)
==785==    by 0x58D24C: do_command(THD*) (sql_parse.cc:945)
==785==    by 0x6434A3: do_handle_one_connection(THD*) (sql_connect.cc:1254)
==785==    by 0x6435E1: handle_one_connection (sql_connect.cc:1168)
==785==    by 0x3679C07D13: start_thread (pthread_create.c:309)
==785==    by 0x36798F168C: clone (clone.S:115)
==785==
==785==
==785== ---- Attach to debugger ? --- [Return/N/n/Y/y/C/c] ---- n
==785== Conditional jump or move depends on uninitialised value(s)
==785==    at 0x5B07E1: build_equal_items_for_cond(THD*, Item*, COND_EQUAL*) (sql_select.cc:11769)
==785==    by 0x5B0C4A: build_equal_items(THD*, Item*, COND_EQUAL*, List<TABLE_LIST>*, COND_EQUAL**) (sql_select.cc:11972)
==785==    by 0x5CB704: JOIN::optimize_inner() (sql_select.cc:13441)
==785==    by 0x5D573E: 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*) (sql_select.cc:985)
==785==    by 0x5D6411: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:362)
==785==    by 0x581957: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:4937)
==785==    by 0x584659: mysql_execute_command(THD*) (sql_parse.cc:2421)
==785==    by 0x58B4C8: mysql_parse(THD*, char*, unsigned int, Parser_state*) (sql_parse.cc:6056)
==785==    by 0x58CC74: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1216)
==785==    by 0x58D24C: do_command(THD*) (sql_parse.cc:945)
==785==    by 0x6434A3: do_handle_one_connection(THD*) (sql_connect.cc:1254)
==785==    by 0x6435E1: handle_one_connection (sql_connect.cc:1168)
==785==    by 0x3679C07D13: start_thread (pthread_create.c:309)
==785==    by 0x36798F168C: clone (clone.S:115)
==785==
==785==
==785== ---- Attach to debugger ? --- [Return/N/n/Y/y/C/c] ---- n
==785== Conditional jump or move depends on uninitialised value(s)
==785==    at 0x5B08C1: build_equal_items_for_cond(THD*, Item*, COND_EQUAL*) (sql_select.cc:11806)
==785==    by 0x5B0C4A: build_equal_items(THD*, Item*, COND_EQUAL*, List<TABLE_LIST>*, COND_EQUAL**) (sql_select.cc:11972)
==785==    by 0x5CB704: JOIN::optimize_inner() (sql_select.cc:13441)
==785==    by 0x5D573E: 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*) (sql_select.cc:985)
==785==    by 0x5D6411: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:362)
==785==    by 0x581957: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:4937)
==785==    by 0x584659: mysql_execute_command(THD*) (sql_parse.cc:2421)
==785==    by 0x58B4C8: mysql_parse(THD*, char*, unsigned int, Parser_state*) (sql_parse.cc:6056)
==785==    by 0x58CC74: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1216)
==785==    by 0x58D24C: do_command(THD*) (sql_parse.cc:945)
==785==    by 0x6434A3: do_handle_one_connection(THD*) (sql_connect.cc:1254)
==785==    by 0x6435E1: handle_one_connection (sql_connect.cc:1168)
==785==    by 0x3679C07D13: start_thread (pthread_create.c:309)
==785==    by 0x36798F168C: clone (clone.S:115)
==785==
==785==
==785== ---- Attach to debugger ? --- [Return/N/n/Y/y/C/c] ---- n
==785== Conditional jump or move depends on uninitialised value(s)
==785==    at 0x710280: Item_cond::update_used_tables() (item_cmpfunc.cc:4544)
==785==    by 0x5B0C59: build_equal_items(THD*, Item*, COND_EQUAL*, List<TABLE_LIST>*, COND_EQUAL**) (sql_select.cc:11973)
==785==    by 0x5CB704: JOIN::optimize_inner() (sql_select.cc:13441)
==785==    by 0x5D573E: 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*) (sql_select.cc:985)
==785==    by 0x5D6411: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:362)
==785==    by 0x581957: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:4937)
==785==    by 0x584659: mysql_execute_command(THD*) (sql_parse.cc:2421)
==785==    by 0x58B4C8: mysql_parse(THD*, char*, unsigned int, Parser_state*) (sql_parse.cc:6056)
==785==    by 0x58CC74: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1216)
==785==    by 0x58D24C: do_command(THD*) (sql_parse.cc:945)
==785==    by 0x6434A3: do_handle_one_connection(THD*) (sql_connect.cc:1254)
==785==    by 0x6435E1: handle_one_connection (sql_connect.cc:1168)
==785==    by 0x3679C07D13: start_thread (pthread_create.c:309)
==785==    by 0x36798F168C: clone (clone.S:115)
==785==
==785==
==785== ---- Attach to debugger ? --- [Return/N/n/Y/y/C/c] ---- n
==785== Conditional jump or move depends on uninitialised value(s)
==785==    at 0x5AA079: propagate_cond_constants(THD*, I_List<COND_CMP>*, Item*, Item*) (sql_select.cc:12644)
==785==    by 0x5CB717: JOIN::optimize_inner() (sql_select.cc:13445)
==785==    by 0x5D573E: 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*) (sql_select.cc:985)
==785==    by 0x5D6411: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:362)
==785==    by 0x581957: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:4937)
==785==    by 0x584659: mysql_execute_command(THD*) (sql_parse.cc:2421)
==785==    by 0x58B4C8: mysql_parse(THD*, char*, unsigned int, Parser_state*) (sql_parse.cc:6056)
==785==    by 0x58CC74: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1216)
==785==    by 0x58D24C: do_command(THD*) (sql_parse.cc:945)
==785==    by 0x6434A3: do_handle_one_connection(THD*) (sql_connect.cc:1254)
==785==    by 0x6435E1: handle_one_connection (sql_connect.cc:1168)
==785==    by 0x3679C07D13: start_thread (pthread_create.c:309)
==785==    by 0x36798F168C: clone (clone.S:115)
==785==
==785==
==785== ---- Attach to debugger ? --- [Return/N/n/Y/y/C/c] ---- n
==785== Conditional jump or move depends on uninitialised value(s)
==785==    at 0x5C482C: internal_remove_eq_conds(THD*, Item*, Item::cond_result*) (sql_select.cc:13490)
==785==    by 0x5C49A5: remove_eq_conds(THD*, Item*, Item::cond_result*) (sql_select.cc:13685)
==785==    by 0x5CB729: JOIN::optimize_inner() (sql_select.cc:13451)
==785==    by 0x5D573E: 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*) (sql_select.cc:985)
==785==    by 0x5D6411: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:362)
==785==    by 0x581957: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:4937)
==785==    by 0x584659: mysql_execute_command(THD*) (sql_parse.cc:2421)
==785==    by 0x58B4C8: mysql_parse(THD*, char*, unsigned int, Parser_state*) (sql_parse.cc:6056)
==785==    by 0x58CC74: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1216)
==785==    by 0x58D24C: do_command(THD*) (sql_parse.cc:945)
==785==    by 0x6434A3: do_handle_one_connection(THD*) (sql_connect.cc:1254)
==785==    by 0x6435E1: handle_one_connection (sql_connect.cc:1168)
==785==    by 0x3679C07D13: start_thread (pthread_create.c:309)
==785==    by 0x36798F168C: clone (clone.S:115)
==785==
==785==
==785== ---- Attach to debugger ? --- [Return/N/n/Y/y/C/c] ---- n
==785== Conditional jump or move depends on uninitialised value(s)
==785==    at 0x7E5504: prune_partitions(THD*, TABLE*, Item*) (opt_range.cc:3411)
==785==    by 0x5CB9B0: JOIN::optimize_inner() (sql_select.cc:1183)
==785==    by 0x5D573E: 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*) (sql_select.cc:985)
==785==    by 0x5D6411: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:362)
==785==    by 0x581957: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:4937)
==785==    by 0x584659: mysql_execute_command(THD*) (sql_parse.cc:2421)
==785==    by 0x58B4C8: mysql_parse(THD*, char*, unsigned int, Parser_state*) (sql_parse.cc:6056)
==785==    by 0x58CC74: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1216)
==785==    by 0x58D24C: do_command(THD*) (sql_parse.cc:945)
==785==    by 0x6434A3: do_handle_one_connection(THD*) (sql_connect.cc:1254)
==785==    by 0x6435E1: handle_one_connection (sql_connect.cc:1168)
==785==    by 0x3679C07D13: start_thread (pthread_create.c:309)
==785==    by 0x36798F168C: clone (clone.S:115)
==785==
==785==
==785== ---- Attach to debugger ? --- [Return/N/n/Y/y/C/c] ---- n
==785== Invalid write of size 4
==785==    at 0x4A0B2CF: memset (mc_replace_strmem.c:1011)
==785==    by 0x5C634B: make_join_statistics(JOIN*, List<TABLE_LIST>&, Item*, st_dynamic_array*) (sql_select.cc:3344)
==785==    by 0x5CBAE1: JOIN::optimize_inner() (sql_select.cc:1263)
==785==    by 0x5D573E: 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*) (sql_select.cc:985)
==785==    by 0x5D6411: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:362)
==785==    by 0x581957: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:4937)
==785==    by 0x584659: mysql_execute_command(THD*) (sql_parse.cc:2421)
==785==    by 0x58B4C8: mysql_parse(THD*, char*, unsigned int, Parser_state*) (sql_parse.cc:6056)
==785==    by 0x58CC74: dispatch_command(enum_server_command, THD*, char*, unsigned int) (sql_parse.cc:1216)
==785==    by 0x58D24C: do_command(THD*) (sql_parse.cc:945)
==785==    by 0x6434A3: do_handle_one_connection(THD*) (sql_connect.cc:1254)
==785==    by 0x6435E1: handle_one_connection (sql_connect.cc:1168)
==785==    by 0x3679C07D13: start_thread (pthread_create.c:309)
==785==    by 0x36798F168C: clone (clone.S:115)
==785==  Address 0x15ae47f8 is 0 bytes after a block of size 8,216 alloc'd
==785==    at 0x4A0881C: malloc (vg_replace_malloc.c:270)
==785==    by 0xAD4E11: my_malloc (my_malloc.c:41)
==785==    by 0xACE08A: reset_root_defaults (my_alloc.c:129)
==785==    by 0x552513: THD::init_for_queries() (sql_class.cc:1401)
==785==    by 0x6418D7: prepare_new_connection_state(THD*) (sql_connect.cc:1101)
==785==    by 0x64331E: thd_prepare_connection(THD*) (sql_connect.cc:1184)
==785==    by 0x643468: do_handle_one_connection(THD*) (sql_connect.cc:1245)
==785==    by 0x6435E1: handle_one_connection (sql_connect.cc:1168)
==785==    by 0x3679C07D13: start_thread (pthread_create.c:309)
==785==    by 0x36798F168C: clone (clone.S:115)
==785==
==785==
==785== ---- Attach to debugger ? --- [Return/N/n/Y/y/C/c] ---- n