Valgrind/MSAN errors in cmp_key_rowid_part_id

--source include/have_partition.inc

CREATE TABLE t (pk int primary key, f int, key (f)) ENGINE=MyISAM PARTITION BY hash(pk) partitions 2;

INSERT INTO t VALUES (1,8),(2,8);

SELECT * FROM t WHERE f IN (8,6);

# Cleanup

DROP TABLE t;

==3006655== Conditional jump or move depends on uninitialised value(s)

==3006655==    at 0x483EEC5: bcmp (vg_replace_strmem.c:1111)

==3006655==    by 0xB4F89A: handler::cmp_ref(unsigned char const*, unsigned char const*) (handler.h:3985)

==3006655==    by 0x13AF128: cmp_key_rowid_part_id (ha_partition.cc:5590)

==3006655==    by 0x14017EB: _downheap (queues.c:304)

==3006655==    by 0x14018BF: queue_fix (queues.c:331)

==3006655==    by 0x13B5B4B: ha_partition::handle_ordered_index_scan(unsigned char*, bool) (ha_partition.cc:7734)

==3006655==    by 0x13B1C3D: ha_partition::multi_range_read_next(void**) (ha_partition.cc:6520)

==3006655==    by 0xCC5E56: QUICK_RANGE_SELECT::get_next() (opt_range.cc:11569)

==3006655==    by 0xCD8A22: rr_quick(READ_RECORD*) (records.cc:369)

==3006655==    by 0x7661B8: READ_RECORD::read_record() (records.h:70)

==3006655==    by 0x887125: join_init_read_record(st_join_table*) (sql_select.cc:20823)

==3006655==    by 0x884C47: sub_select(JOIN*, st_join_table*, bool) (sql_select.cc:19878)

==3006655==    by 0x8840B4: do_select(JOIN*, Procedure*) (sql_select.cc:19419)

==3006655==    by 0x85A9DD: JOIN::exec_inner() (sql_select.cc:4150)

==3006655==    by 0x859D9D: JOIN::exec() (sql_select.cc:3944)

==3006655==    by 0x85B0CC: mysql_select(THD*, 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:4353)

==3006655== Conditional jump or move depends on uninitialised value(s)

==3006655==    at 0x13AF135: cmp_key_rowid_part_id (ha_partition.cc:5590)

==3006655==    by 0x14017EB: _downheap (queues.c:304)

==3006655==    by 0x14018BF: queue_fix (queues.c:331)

==3006655==    by 0x13B5B4B: ha_partition::handle_ordered_index_scan(unsigned char*, bool) (ha_partition.cc:7734)

==3006655==    by 0x13B1C3D: ha_partition::multi_range_read_next(void**) (ha_partition.cc:6520)

==3006655==    by 0xCC5E56: QUICK_RANGE_SELECT::get_next() (opt_range.cc:11569)

==3006655==    by 0xCD8A22: rr_quick(READ_RECORD*) (records.cc:369)

==3006655==    by 0x7661B8: READ_RECORD::read_record() (records.h:70)

==3006655==    by 0x887125: join_init_read_record(st_join_table*) (sql_select.cc:20823)

==3006655==    by 0x884C47: sub_select(JOIN*, st_join_table*, bool) (sql_select.cc:19878)

==3006655==    by 0x8840B4: do_select(JOIN*, Procedure*) (sql_select.cc:19419)

==3006655==    by 0x85A9DD: JOIN::exec_inner() (sql_select.cc:4150)

==3006655==    by 0x859D9D: JOIN::exec() (sql_select.cc:3944)

==3006655==    by 0x85B0CC: mysql_select(THD*, 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:4353)

==3006655==    by 0x84C4E8: handle_select(THD*, LEX*, select_result*, unsigned long) (sql_select.cc:372)

==3006655==    by 0x812A35: execute_sqlcom_select(THD*, TABLE_LIST*) (sql_parse.cc:6339)

Uninitialized bytes in MemcmpInterceptorCommon at offset 0 inside [0x706000013965, 7)

==32155==WARNING: MemorySanitizer: use-of-uninitialized-value

    #0 0x555a8c4f560e in memcmp (/home/jenkins/10.5/sql/mariadbd+0x71960e)

    #1 0x555a8e3b2c1f in cmp_key_rowid_part_id /home/jenkins/10.5/sql/ha_partition.cc:5761:43

    #2 0x555a8f880d8c in _downheap /home/jenkins/10.5/mysys/queues.c:305:10

    #3 0x555a8f880d8c in queue_fix /home/jenkins/10.5/mysys/queues.c:332:5

    #4 0x555a8e3b8ed5 in ha_partition::handle_ordered_index_scan(unsigned char*, bool) /home/jenkins/10.5/sql/ha_partition.cc:7892:5

    #5 0x555a8e3c87ef in ha_partition::multi_range_read_next(void**) /home/jenkins/10.5/sql/ha_partition.cc:6684:11

    #6 0x555a8dd10a96 in QUICK_RANGE_SELECT::get_next() /home/jenkins/10.5/sql/opt_range.cc:12687:5

    #7 0x555a8dd66a31 in rr_quick(READ_RECORD*) /home/jenkins/10.5/sql/records.cc:403:37

    #8 0x555a8cba11c9 in READ_RECORD::read_record() /home/jenkins/10.5/sql/records.h:80:30

    #9 0x555a8cba11c9 in join_init_read_record(st_join_table*) /home/jenkins/10.5/sql/sql_select.cc:21877:27

    #10 0x555a8cc332fb in sub_select(JOIN*, st_join_table*, bool) /home/jenkins/10.5/sql/sql_select.cc:20910:12

    #11 0x555a8cbab60a in do_select(JOIN*, Procedure*) /home/jenkins/10.5/sql/sql_select.cc:20445:14

    #12 0x555a8cbab60a in JOIN::exec_inner() /home/jenkins/10.5/sql/sql_select.cc:4538:50

    #13 0x555a8cba750c in JOIN::exec() /home/jenkins/10.5/sql/sql_select.cc:4318:3

    #14 0x555a8cb11c93 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*) /home/jenkins/10.5/sql/sql_select.cc:4795:9

    #15 0x555a8cb10a58 in handle_select(THD*, LEX*, select_result*, unsigned long) /home/jenkins/10.5/sql/sql_select.cc:444:10

    #16 0x555a8ca47755 in execute_sqlcom_select(THD*, TABLE_LIST*) /home/jenkins/10.5/sql/sql_parse.cc:6314:12

    #17 0x555a8ca214a8 in mysql_execute_command(THD*) /home/jenkins/10.5/sql/sql_parse.cc:4005:12

    #18 0x555a8ca08938 in mysql_parse(THD*, char*, unsigned int, Parser_state*, bool, bool) /home/jenkins/10.5/sql/sql_parse.cc:8100:18

    #19 0x555a8c9fbbfc in dispatch_command(enum_server_command, THD*, char*, unsigned int, bool, bool) /home/jenkins/10.5/sql/sql_parse.cc:1891:7

    #20 0x555a8ca0a8ac in do_command(THD*) /home/jenkins/10.5/sql/sql_parse.cc:1370:17

    #21 0x555a8cffe929 in do_handle_one_connection(CONNECT*, bool) /home/jenkins/10.5/sql/sql_connect.cc:1418:11

    #22 0x555a8cffe045 in handle_one_connection /home/jenkins/10.5/sql/sql_connect.cc:1312:5

    #23 0x555a8e3ff86a in pfs_spawn_thread /home/jenkins/10.5/storage/perfschema/pfs.cc:2201:3

    #24 0x7f8b06acf608 in start_thread /build/glibc-eX1tMB/glibc-2.31/nptl/pthread_create.c:477:8

    #25 0x7f8b067d4292 in clone /build/glibc-eX1tMB/glibc-2.31/misc/../sysdeps/unix/sysv/linux/x86_64/clone.S:95

  Memory was marked as uninitialized

    #0 0x555a8c4f19ae in __msan_allocated_memory (/home/jenkins/10.5/sql/mariadbd+0x7159ae)

    #1 0x555a8f868900 in my_malloc /home/jenkins/10.5/mysys/my_malloc.c:113:7

SUMMARY: MemorySanitizer: use-of-uninitialized-value (/home/jenkins/10.5/sql/mariadbd+0x71960e) in memcmp