Server crash or ASAN use-after-poison in fk_prepare_copy_alter_table upon dropping FK

--source include/have_innodb.inc

CREATE TABLE tx (pk INT PRIMARY KEY) ENGINE=InnoDB;

CREATE TABLE t1 (a INT, CONSTRAINT fk FOREIGN KEY (a) REFERENCES tx(pk)) ENGINE=InnoDB;

ALTER IGNORE TABLE t1 DROP FOREIGN KEY fk, DROP FOREIGN KEY fk, ALGORITHM=COPY;

# Cleanup

DROP TABLE t1, tx;

==21826==ERROR: AddressSanitizer: use-after-poison on address 0x557aba8bd568 at pc 0x557ab775e79f bp 0x7f5597b04240 sp 0x7f5597b04238

READ of size 8 at 0x557aba8bd568 thread T27

    #0 0x557ab775e79e in base_list_iterator::next_fast() /data/src/10.3/sql/sql_list.h:433

    #1 0x557ab7c140d6 in List_iterator_fast<Alter_drop>::operator++(int) /data/src/10.3/sql/sql_list.h:554

    #2 0x557ab7c02708 in fk_prepare_copy_alter_table /data/src/10.3/sql/sql_table.cc:8770

    #3 0x557ab7c077b7 in mysql_alter_table(THD*, st_mysql_const_lex_string const*, st_mysql_const_lex_string const*, HA_CREATE_INFO*, TABLE_LIST*, Alter_info*, unsigned int, st_order*, bool) /data/src/10.3/sql/sql_table.cc:9771

    #4 0x557ab7d52ecd in Sql_cmd_alter_table::execute(THD*) /data/src/10.3/sql/sql_alter.cc:494

    #5 0x557ab79ee21a in mysql_execute_command(THD*) /data/src/10.3/sql/sql_parse.cc:6285

    #6 0x557ab79f90a9 in mysql_parse(THD*, char*, unsigned int, Parser_state*, bool, bool) /data/src/10.3/sql/sql_parse.cc:8091

    #7 0x557ab79d31d1 in dispatch_command(enum_server_command, THD*, char*, unsigned int, bool, bool) /data/src/10.3/sql/sql_parse.cc:1857

    #8 0x557ab79d0227 in do_command(THD*) /data/src/10.3/sql/sql_parse.cc:1403

    #9 0x557ab7d43f7f in do_handle_one_connection(CONNECT*) /data/src/10.3/sql/sql_connect.cc:1402

    #10 0x557ab7d4398b in handle_one_connection /data/src/10.3/sql/sql_connect.cc:1308

    #11 0x557ab887a131 in pfs_spawn_thread /data/src/10.3/storage/perfschema/pfs.cc:1862

    #12 0x7f55a3660493 in start_thread (/lib/x86_64-linux-gnu/libpthread.so.0+0x7493)

    #13 0x7f55a182e93e in __clone (/lib/x86_64-linux-gnu/libc.so.6+0xe893e)

0x557aba8bd568 is located 8 bytes inside of global variable 'end_of_list' from '/data/src/10.3/sql/sql_list.cc' (0x557aba8bd560) of size 16

SUMMARY: AddressSanitizer: use-after-poison /data/src/10.3/sql/sql_list.h:433 base_list_iterator::next_fast()

Shadow bytes around the buggy address:

  0x0aafd750fa50: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

  0x0aafd750fa60: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

  0x0aafd750fa70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

  0x0aafd750fa80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

  0x0aafd750fa90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

=>0x0aafd750faa0: 00 00 00 00 00 00 00 00 f9 f9 f9 f9 f7[f7]f9 f9

  0x0aafd750fab0: f9 f9 f9 f9 00 00 00 00 01 f9 f9 f9 f9 f9 f9 f9

  0x0aafd750fac0: 01 f9 f9 f9 f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9

  0x0aafd750fad0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

  0x0aafd750fae0: 00 00 00 00 00 00 f9 f9 f9 f9 f9 f9 00 00 00 00

  0x0aafd750faf0: 00 00 00 f9 f9 f9 f9 f9 00 f9 f9 f9 f9 f9 f9 f9

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

  Heap right redzone:      fb

  Freed heap region:       fd

  Stack left redzone:      f1

  Stack mid redzone:       f2

  Stack right redzone:     f3

  Stack partial redzone:   f4

  Stack after return:      f5

  Stack use after scope:   f8

  Global redzone:          f9

  Global init order:       f6

  Poisoned by user:        f7

  Contiguous container OOB:fc

  ASan internal:           fe

Thread T27 created by T0 here:

    #0 0x7f55a3899bba in pthread_create (/usr/lib/x86_64-linux-gnu/libasan.so.1+0x23bba)

    #1 0x557ab887a6f9 in spawn_thread_v1 /data/src/10.3/storage/perfschema/pfs.cc:1912

    #2 0x557ab773bb88 in inline_mysql_thread_create /data/src/10.3/include/mysql/psi/mysql_thread.h:1268

    #3 0x557ab775151e in create_thread_to_handle_connection(CONNECT*) /data/src/10.3/sql/mysqld.cc:6589

    #4 0x557ab7751c23 in create_new_thread /data/src/10.3/sql/mysqld.cc:6659

    #5 0x557ab7752c3a in handle_connections_sockets() /data/src/10.3/sql/mysqld.cc:6934

    #6 0x557ab77509db in mysqld_main(int, char**) /data/src/10.3/sql/mysqld.cc:6211

    #7 0x557ab7739c0f in main /data/src/10.3/sql/main.cc:25

    #8 0x7f55a17662b0 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x202b0)

==21826==ABORTING

#3  <signal handler called>

#4  0x0000559ff23c3e06 in fk_prepare_copy_alter_table (thd=0x7f9a70000b00, table=0x7f9a700a8690, alter_info=0x7f9abeb50be0, alter_ctx=0x7f9abeb500b0) at /data/src/10.3/sql/sql_table.cc:8773

#5  0x0000559ff23c6783 in mysql_alter_table (thd=0x7f9a70000b00, new_db=0x7f9a700051d0, new_name=0x7f9a70005590, create_info=0x7f9abeb50ca0, table_list=0x7f9a70014e30, alter_info=0x7f9abeb50be0, order_num=0, order=0x0, ignore=true) at /data/src/10.3/sql/sql_table.cc:9771

#6  0x0000559ff244e902 in Sql_cmd_alter_table::execute (this=0x7f9a700154d8, thd=0x7f9a70000b00) at /data/src/10.3/sql/sql_alter.cc:494

#7  0x0000559ff22ef4ca in mysql_execute_command (thd=0x7f9a70000b00) at /data/src/10.3/sql/sql_parse.cc:6285

#8  0x0000559ff22f456f in mysql_parse (thd=0x7f9a70000b00, rawbuf=0x7f9a70014ce8 "ALTER IGNORE TABLE t1 DROP FOREIGN KEY fk, DROP FOREIGN KEY fk, ALGORITHM=COPY", length=78, parser_state=0x7f9abeb525f0, is_com_multi=false, is_next_command=false) at /data/src/10.3/sql/sql_parse.cc:8091

#9  0x0000559ff22e183e in dispatch_command (command=COM_QUERY, thd=0x7f9a70000b00, packet=0x7f9a70162261 "ALTER IGNORE TABLE t1 DROP FOREIGN KEY fk, DROP FOREIGN KEY fk, ALGORITHM=COPY", packet_length=78, is_com_multi=false, is_next_command=false) at /data/src/10.3/sql/sql_parse.cc:1857

#10 0x0000559ff22e0228 in do_command (thd=0x7f9a70000b00) at /data/src/10.3/sql/sql_parse.cc:1403

#11 0x0000559ff2448ec1 in do_handle_one_connection (connect=0x559ff4b9add0) at /data/src/10.3/sql/sql_connect.cc:1402

#12 0x0000559ff2448c45 in handle_one_connection (arg=0x559ff4b9add0) at /data/src/10.3/sql/sql_connect.cc:1308

#13 0x0000559ff28e5519 in pfs_spawn_thread (arg=0x559ff4ae0190) at /data/src/10.3/storage/perfschema/pfs.cc:1862

#14 0x00007f9acb6ff494 in start_thread (arg=0x7f9abeb53700) at pthread_create.c:333

#15 0x00007f9ac98cd93f in clone () from /lib/x86_64-linux-gnu/libc.so.6