ASAN global-buffer-overflow at json_scan_next

SELECT JSON_KEYS(REPEAT('{ "a" : "foo", "b" : [ true,', 100));

 CC=clang-12 CXX=clang++-12 cmake ../mariadb -DWITH_ASAN=ON

=================================================================

==107603==ERROR: AddressSanitizer: global-buffer-overflow on address 0x000003308f50 at pc 0x0000024c2592 bp 0x7f376610d830 sp 0x7f376610d828

READ of size 8 at 0x000003308f50 thread T11

    #0 0x24c2591 in json_scan_next /root/mariadb/strings/json_lib.c:977:28

    #1 0x24c2591 in v_true /root/mariadb/strings/json_lib.c:612:10

    #2 0x24b46e5 in json_scan_next /root/mariadb/strings/json_lib.c:977:28

    #3 0x109ce91 in Item_func_json_keys::val_str(String*) /root/mariadb/sql/item_jsonfunc.cc:3704:10

    #4 0x11831a9 in Type_handler::Item_send_str(Item*, Protocol*, st_value*) const /root/mariadb/sql/sql_type.cc:7496:19

    #5 0x90ea0a in Protocol::send_result_set_row(List<Item>*) /root/mariadb/sql/protocol.cc:1333:15

    #6 0xa7584c in select_send::send_data(List<Item>&) /root/mariadb/sql/sql_class.cc:3187:17

    #7 0xcb3d4d in select_result_sink::send_data_with_check(List<Item>&, st_select_lex_unit*, unsigned long long) /root/mariadb/sql/sql_class.h:5995:12

    #8 0xcb3d4d in JOIN::exec_inner() /root/mariadb/sql/sql_select.cc:4862:22

    #9 0xcb1198 in JOIN::exec() /root/mariadb/sql/sql_select.cc:4774:8

    #10 0xc527c7 in mysql_select(THD*, TABLE_LIST*, List<Item>&, Item*, unsigned int, st_order*, st_order*, Item*, st_order*, unsigned long long, select_result*, st_select_lex_unit*, st_select_lex*) /root/mariadb/sql/sql_select.cc:5304:21

    #11 0xc51c68 in handle_select(THD*, LEX*, select_result*, unsigned long long) /root/mariadb/sql/sql_select.cc:630:10

    #12 0xba71f1 in execute_sqlcom_select(THD*, TABLE_LIST*) /root/mariadb/sql/sql_parse.cc:6094:12

    #13 0xb95e8b in mysql_execute_command(THD*, bool) /root/mariadb/sql/sql_parse.cc:3943:12

    #14 0xc22e52 in Prepared_statement::execute(String*, bool) /root/mariadb/sql/sql_prepare.cc:5076:14

    #15 0xc1c93a in Prepared_statement::execute_loop(String*, bool, unsigned char*, unsigned char*) /root/mariadb/sql/sql_prepare.cc:4461:10

    #16 0xc1b646 in mysql_stmt_execute_common(THD*, unsigned long, unsigned char*, unsigned char*, unsigned long, bool, bool) /root/mariadb/sql/sql_prepare.cc:3368:11

    #17 0xc1affe in mysqld_stmt_execute(THD*, char*, unsigned int) /root/mariadb/sql/sql_prepare.cc:3139:3

    #18 0xb81a77 in dispatch_command(enum_server_command, THD*, char*, unsigned int, bool) /root/mariadb/sql/sql_parse.cc:1818:5

    #19 0xb89c41 in do_command(THD*, bool) /root/mariadb/sql/sql_parse.cc:1406:17

    #20 0xf82df8 in do_handle_one_connection(CONNECT*, bool) /root/mariadb/sql/sql_connect.cc:1437:11

    #21 0xf82848 in handle_one_connection /root/mariadb/sql/sql_connect.cc:1339:5

    #22 0x1b267da in pfs_spawn_thread /root/mariadb/storage/perfschema/pfs.cc:2201:3

    #23 0x7f378a6ad608 in start_thread /build/glibc-e2p3jK/glibc-2.31/nptl/pthread_create.c:477:8

    #24 0x7f378a3c3352 in clone /build/glibc-e2p3jK/glibc-2.31/misc/../sysdeps/unix/sysv/linux/x86_64/clone.S:95

0x000003308f50 is located 248 bytes to the right of global variable 'vtable for ha_myisammrg' defined in '/root/mariadb/storage/myisammrg/ha_myisammrg.cc' (0x33087c0) of size 1688

SUMMARY: AddressSanitizer: global-buffer-overflow /root/mariadb/strings/json_lib.c:977:28 in json_scan_next

Shadow bytes around the buggy address:

  0x000080659190: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

  0x0000806591a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

  0x0000806591b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

  0x0000806591c0: 00 00 00 00 00 00 00 00 00 00 00 f9 f9 f9 f9 f9

  0x0000806591d0: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9

=>0x0000806591e0: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9[f9]f9 f9 f9 f9 f9

  0x0000806591f0: f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9 f9

  0x000080659200: 00 00 00 f9 f9 f9 f9 f9 00 00 00 00 00 00 00 00

  0x000080659210: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

  0x000080659220: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

  0x000080659230: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Shadow byte legend (one shadow byte represents 8 application bytes):

  Addressable:           00

  Partially addressable: 01 02 03 04 05 06 07 

  Heap left redzone:       fa

  Freed heap region:       fd

  Stack left redzone:      f1

  Stack mid redzone:       f2

  Stack right redzone:     f3

  Stack after return:      f5

  Stack use after scope:   f8

  Global redzone:          f9

  Global init order:       f6

  Poisoned by user:        f7

  Container overflow:      fc

  Array cookie:            ac

  Intra object redzone:    bb

  ASan internal:           fe

  Left alloca redzone:     ca

  Right alloca redzone:    cb

  Shadow gap:              cc

Thread T11 created by T0 here:

    #0 0x8161fc in pthread_create (/root/bin_original/usr/local/mysql/bin/mariadbd+0x8161fc)

    #1 0x1b26a9d in my_thread_create(unsigned long*, pthread_attr_t const*, void* (*)(void*), void*) /root/mariadb/storage/perfschema/my_thread.h:52:10

    #2 0x1b26a9d in pfs_spawn_thread_v1 /root/mariadb/storage/perfschema/pfs.cc:2252:15

    #3 0x871689 in inline_mysql_thread_create(unsigned int, unsigned long*, pthread_attr_t const*, void* (*)(void*), void*) /root/mariadb/include/mysql/psi/mysql_thread.h:1139:11

    #4 0x871689 in create_thread_to_handle_connection(CONNECT*) /root/mariadb/sql/mysqld.cc:6074:19

    #5 0x872518 in create_new_thread(CONNECT*) /root/mariadb/sql/mysqld.cc:6136:3

    #6 0x872518 in handle_accepted_socket(st_mysql_socket, st_mysql_socket) /root/mariadb/sql/mysqld.cc:6198:5

    #7 0x86f988 in handle_connections_sockets() /root/mariadb/sql/mysqld.cc:6311:9

    #8 0x86714a in mysqld_main(int, char**) /root/mariadb/sql/mysqld.cc:5969:3

    #9 0x7f378a2c8082 in __libc_start_main /build/glibc-e2p3jK/glibc-2.31/csu/../csu/libc-start.c:308:16

==107603==ABORTING