Assertion DBUG_ASSERT(thd->lock == 0) failed in lock_tables()

CREATE OR REPLACE TABLE t1(a INT, b INT);

DELIMITER $$

CREATE OR REPLACE FUNCTION f() RETURNS INT

BEGIN

  EXECUTE IMMEDIATE 'SELECT 1';

  RETURN 5;

END;

$$

CREATE TRIGGER tr AFTER INSERT ON t1 FOR EACH ROW

BEGIN

  UPDATE t1 SET b=f();

END;

$$

DELIMITER ;

INSERT INTO t1(a) VALUES (1);

#1  0x00007ffff7028f0e in raise () from /lib64/libc.so.6

#2  0x00007ffff70106d0 in abort () from /lib64/libc.so.6

#3  0x00007ffff7010639 in __assert_fail_base.cold () from /lib64/libc.so.6

#4  0x000055555568c914 in lock_tables (thd=0x77ffa8000dd0, 

    tables=0x77ffa8090b30, count=1, flags=0)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sql_base.cc:6058

#5  0x0000555555845d2d in Sql_cmd_dml::execute (this=0x77ffa8091610, 

    thd=0x77ffa8000dd0)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sql_select.cc:34989

#6  0x000055555576bb30 in mysql_execute_command (thd=0x77ffa8000dd0, 

    is_called_from_prepared_stmt=false)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sql_parse.cc:4446

#7  0x0000555555ac14ef in sp_instr_stmt::exec_core (this=0x77ffa80b91b0, 

    thd=0x77ffa8000dd0, nextp=0x7fffe009d92c)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sp_instr.cc:1281

#8  0x0000555555abf379 in sp_lex_keeper::reset_lex_and_exec_core (

    this=0x77ffa80b91f0, thd=0x77ffa8000dd0, nextp=0x7fffe009d92c, 

    open_tables=false, instr=0x77ffa80b91b0, rerun_the_same_instr=false)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sp_instr.cc:420

#9  0x0000555555abfa43 in sp_lex_keeper::validate_lex_and_exec_core (

    this=0x77ffa80b91f0, thd=0x77ffa8000dd0, nextp=0x7fffe009d92c, 

    open_tables=false, instr=0x77ffa80b91b0)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sp_instr.cc:599

#10 0x0000555555ac1011 in sp_instr_stmt::execute (this=0x77ffa80b91b0, 

    thd=0x77ffa8000dd0, nextp=0x7fffe009d92c)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sp_instr.cc:1183

#11 0x0000555555626f02 in sp_head::execute (this=0x77ffa808f760, 

    thd=0x77ffa8000dd0, merge_da_on_success=false)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sp_head.cc:1292

#12 0x00005555556286fb in sp_head::execute_trigger (this=0x77ffa808f760, 

    thd=0x77ffa8000dd0, db_name=0x77ffa8095ed8, table_name=0x77ffa8095ee8, 

    grant_info=0x77ffa80c01c8)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sp_head.cc:1805

#13 0x00005555558e9762 in Table_triggers_list::process_triggers (

    this=0x77ffa80bfc20, thd=0x77ffa8000dd0, event=TRG_EVENT_INSERT, 

    time_type=TRG_ACTION_AFTER, old_row_is_record1=true, 

    skip_row_indicator=0x0, fields_in_update_stmt=0x0)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sql_trigger.cc:2847

#14 0x000055555570c8c3 in Write_record::after_ins_trg (this=0x7fffe009e4e0)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sql_insert.cc:2548

#15 0x000055555570c845 in Write_record::after_insert (this=0x7fffe009e4e0, 

    inserted=0x7fffe009e2e0)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sql_insert.cc:2540

#16 0x00005555556ffe29 in Write_record::single_insert (this=0x7fffe009e4e0, 

    inserted=0x7fffe009e2e0)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sql_insert.cc:2401

#17 0x00005555556ffec2 in Write_record::write_record (this=0x7fffe009e4e0)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sql_insert.cc:2431

#18 0x00005555556fc2dc in mysql_insert (thd=0x77ffa8000dd0, 

    table_list=0x77ffa80353e0, fields=..., values_list=..., update_fields=..., 

    update_values=..., duplic=DUP_ERROR, ignore=false, result=0x0)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sql_insert.cc:1232

#19 0x000055555576bfed in mysql_execute_command (thd=0x77ffa8000dd0, 

    is_called_from_prepared_stmt=false)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sql_parse.cc:4502

#20 0x0000555555777dca in mysql_parse (thd=0x77ffa8000dd0, 

    rawbuf=0x77ffa80352d0 "INSERT INTO t1(a) VALUES (1)", length=28, 

    parser_state=0x7fffe009ef40)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sql_parse.cc:7945

#21 0x000055555576295a in dispatch_command (command=COM_QUERY, 

    thd=0x77ffa8000dd0, packet=0x77ffa800c3f1 "INSERT INTO t1(a) VALUES (1)", 

    packet_length=28, blocking=true)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sql_parse.cc:1903

#22 0x0000555555761067 in do_command (thd=0x77ffa8000dd0, blocking=true)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sql_parse.cc:1437

#23 0x00005555559ad192 in do_handle_one_connection (connect=0x5555597864e0, 

    put_in_cache=true)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sql_connect.cc:1503

#24 0x00005555559acedf in handle_one_connection (arg=0x5555597864e0)

    at /home/bar/maria-git/13.1.m39518.fnc4/sql/sql_connect.cc:1415

#25 0x0000555556045fd8 in pfs_spawn_thread (arg=0x555559784070)

    at /home/bar/maria-git/13.1.m39518.fnc4/storage/perfschema/pfs.cc:2198

#26 0x00007ffff7080f34 in start_thread () from /lib64/libc.so.6

#27 0x00007ffff710436c in __clone3 () from /lib64/libc.so.6