Server crashes in Rows_log_event::find_row upon concurrent DML and ALTER

--source include/have_debug_sync.inc

CREATE TABLE t (a INT, b INT, KEY id(b));

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

--connect (con1,localhost,root,,)

SET debug_sync= 'alter_table_online_before_lock SIGNAL doupdate WAIT_FOR goforit';

--send

  ALTER TABLE t MODIFY COLUMN IF EXISTS id SERIAL FIRST, ALGORITHM=COPY, LOCK=NONE;

--connection default

SET debug_sync='now WAIT_FOR doupdate';

UPDATE t SET a = 116 LIMIT 1;

SET debug_sync='now SIGNAL goforit';

--connection con1

--reap

# Cleanup

DROP TABLE t;

--disconnect con1

#3  <signal handler called>

#4  0x000056214572fb6c in Rows_log_event::find_row (this=0x7f51e8026408, rgi=0x7f52056d4f50) at /data/src/bb-11.0-oalter-debug/sql/log_event_server.cc:7380

#5  0x000056214573173f in Update_rows_log_event::do_exec_row (this=0x7f51e8026408, rgi=0x7f52056d4f50) at /data/src/bb-11.0-oalter-debug/sql/log_event_server.cc:7879

#6  0x000056214572828f in Rows_log_event::do_apply_event (this=0x7f51e8026408, rgi=0x7f52056d4f50) at /data/src/bb-11.0-oalter-debug/sql/log_event_server.cc:5085

#7  0x000056214571275c in Log_event::apply_event (this=0x7f51e8026408, rgi=0x7f52056d4f50) at /data/src/bb-11.0-oalter-debug/sql/log_event.cc:3861

#8  0x00005621452cfe32 in online_alter_read_from_binlog (thd=0x7f51e8000dc8, rgi=0x7f52056d4f50, log=0x7f51e80277f0, unsafe_autoinc=true) at /data/src/bb-11.0-oalter-debug/sql/sql_table.cc:11649

#9  0x00005621452d1bb6 in copy_data_between_tables (thd=0x7f51e8000dc8, from=0x7f51f419a058, to=0x7f51e801fe18, create=..., ignore=false, order_num=0, order=0x0, copied=0x7f52056d8e50, deleted=0x7f52056d8e58, keys_onoff=Alter_info::LEAVE_AS_IS, alter_ctx=0x7f52056da420, online=true, online_unsafe_autoinc=true) at /data/src/bb-11.0-oalter-debug/sql/sql_table.cc:12089

#10 0x00005621452ce313 in mysql_alter_table (thd=0x7f51e8000dc8, new_db=0x7f51e8005ae0, new_name=0x7f51e8005f28, create_info=0x7f52056db240, table_list=0x7f51e8014128, recreate_info=0x7f52056db110, alter_info=0x7f52056db150, order_num=0, order=0x0, ignore=false, if_exists=false) at /data/src/bb-11.0-oalter-debug/sql/sql_table.cc:11112

#11 0x000056214538ca23 in Sql_cmd_alter_table::execute (this=0x7f51e8014a40, thd=0x7f51e8000dc8) at /data/src/bb-11.0-oalter-debug/sql/sql_alter.cc:563

#12 0x000056214519cd9f in mysql_execute_command (thd=0x7f51e8000dc8, is_called_from_prepared_stmt=false) at /data/src/bb-11.0-oalter-debug/sql/sql_parse.cc:6001

#13 0x00005621451a2f16 in mysql_parse (thd=0x7f51e8000dc8, rawbuf=0x7f51e8013fe0 "ALTER TABLE t MODIFY COLUMN IF EXISTS id SERIAL FIRST, ALGORITHM=COPY, LOCK=NONE", length=80, parser_state=0x7f52056dc370) at /data/src/bb-11.0-oalter-debug/sql/sql_parse.cc:7997

#14 0x000056214518eb81 in dispatch_command (command=COM_QUERY, thd=0x7f51e8000dc8, packet=0x7f51e800ba79 "", packet_length=80, blocking=true) at /data/src/bb-11.0-oalter-debug/sql/sql_parse.cc:1894

#15 0x000056214518d4e8 in do_command (thd=0x7f51e8000dc8, blocking=true) at /data/src/bb-11.0-oalter-debug/sql/sql_parse.cc:1407

#16 0x0000562145380e62 in do_handle_one_connection (connect=0x5621484f6a98, put_in_cache=true) at /data/src/bb-11.0-oalter-debug/sql/sql_connect.cc:1416

#17 0x0000562145380bd7 in handle_one_connection (arg=0x5621484f6a98) at /data/src/bb-11.0-oalter-debug/sql/sql_connect.cc:1318

#18 0x00005621458a131a in pfs_spawn_thread (arg=0x5621484f6b78) at /data/src/bb-11.0-oalter-debug/storage/perfschema/pfs.cc:2201

#19 0x00007f520b8a7fd4 in start_thread (arg=<optimized out>) at ./nptl/pthread_create.c:442

#20 0x00007f520b9285bc in clone3 () at ../sysdeps/unix/sysv/linux/x86_64/clone3.S:81