Unhandled deadlock (hang) between DML and online alter table

--source include/have_innodb.inc

--source include/have_sequence.inc

--source include/have_debug_sync.inc

CREATE TABLE t1(a INT PRIMARY KEY) ENGINE=InnoDB;

INSERT INTO t1 SELECT seq FROM seq_1_to_10;

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

SET debug_sync= 'alter_table_online_before_lock SIGNAL before_upgrade WAIT_FOR cont2';

send REPAIR TABLE t1;

--connection default

SET debug_sync= 'now WAIT_FOR before_upgrade';

BEGIN;

send DELETE FROM t1 WHERE a=3;

--connect(con2,localhost,root,,)

# ToDo anything better we can do here than a sleep? Perhaps waiting for processlist state

--sleep 0.1

SET debug_sync= 'now SIGNAL cont2';

--sleep 0.1

--connection default

reap;

COMMIT;

--connection con1

reap;

SELECT COUNT(*) FROM t1;

DROP TABLE t1;

Thread 10 (Thread 0x7f5d8294a6c0 (LWP 1795466)):

#7  0x000055cfde5a762c in safe_cond_timedwait (cond=0x7f5d83197c50, mp=0x55cfdfb5e700 <lock_sys+192>, abstime=0x7f5d82947d10, file=0x55cfde8dd9e2 "/kvm/src/my/dev/mariadb3/storage/innobase/lock/lock0lock.cc", line=2382) at /kvm/src/my/dev/mariadb3/mysys/thr_mutex.c:543

#8  0x000055cfde2987f1 in lock_wait (thr=thr@entry=0x7f5d58272ae8) at /kvm/src/my/dev/mariadb3/storage/innobase/lock/lock0lock.cc:2381

#9  0x000055cfde37b9b6 in row_mysql_handle_errors (new_err=new_err@entry=0x7f5d82947fa4, trx=trx@entry=0x7f5d83197bc0, thr=thr@entry=0x7f5d58272ae8, savept=savept@entry=0x0) at /kvm/src/my/dev/mariadb3/storage/innobase/row/row0mysql.cc:698

#10 0x000055cfde3b0511 in row_search_mvcc (buf=buf@entry=0x7f5d5806fa80 "\377", mode=<optimized out>, prebuilt=0x7f5d58272540, match_mode=1, direction=direction@entry=0) at /kvm/src/my/dev/mariadb3/storage/innobase/row/row0sel.cc:5872

#11 0x000055cfde23128e in ha_innobase::index_read (this=0x7f5d5806f228, buf=0x7f5d5806fa80 "\377", key_ptr=0x7f5d58074dd0 "\003", key_len=4, find_flag=HA_READ_KEY_EXACT) at /kvm/src/my/dev/mariadb3/storage/innobase/handler/ha_innodb.cc:9035

#12 0x000055cfddf404d4 in handler::ha_index_read_map (this=this@entry=0x7f5d5806f228, buf=0x7f5d5806fa80 "\377", key=0x7f5d58074dd0 "\003", keypart_map=1, find_flag=HA_READ_KEY_EXACT) at /kvm/src/my/dev/mariadb3/sql/handler.cc:3875

#13 0x000055cfddf492ed in handler::read_range_first (this=0x7f5d5806f228, start_key=0x7f5d5806f388, end_key=0x7f5d5806f3a8, eq_range_arg=true, sorted=<optimized out>) at /kvm/src/my/dev/mariadb3/sql/handler.cc:7206

#14 0x000055cfdddf229a in handler::multi_range_read_next (this=0x7f5d5806f228, range_info=range_info@entry=0x7f5d82948a40) at /kvm/src/my/dev/mariadb3/sql/multi_range_read.cc:590

#15 0x000055cfdddf23fc in Mrr_simple_index_reader::get_next (this=0x7f5d5806f900, range_info=0x7f5d82948a40) at /kvm/src/my/dev/mariadb3/sql/multi_range_read.cc:627

#16 0x000055cfdddf434f in DsMrr_impl::dsmrr_next (this=0x7f5d5806f7b0, range_info=0x7f5d82948a40) at /kvm/src/my/dev/mariadb3/sql/multi_range_read.cc:1731

#17 0x000055cfddb412fa in QUICK_RANGE_SELECT::get_next (this=0x7f5d58072010) at /kvm/src/my/dev/mariadb3/sql/opt_range.cc:13509

#18 0x000055cfddb5e091 in rr_quick (info=0x7f5d82948ba0) at /kvm/src/my/dev/mariadb3/sql/records.cc:398

#19 0x000055cfddbf9d5a in READ_RECORD::read_record (this=0x7f5d82948ba0) at /kvm/src/my/dev/mariadb3/sql/records.h:77

#20 Sql_cmd_delete::delete_from_single_table (this=this@entry=0x7f5d58017930, thd=thd@entry=0x7f5d58000d58) at /kvm/src/my/dev/mariadb3/sql/sql_delete.cc:861

#21 0x000055cfddbfcecc in Sql_cmd_delete::execute_inner (this=0x7f5d58017930, thd=0x7f5d58000d58) at /kvm/src/my/dev/mariadb3/sql/sql_delete.cc:2083

#22 0x000055cfddcdd0b6 in Sql_cmd_dml::execute (this=0x7f5d58017930, thd=0x7f5d58000d58) at /kvm/src/my/dev/mariadb3/sql/sql_select.cc:34525

#23 0x000055cfddc48581 in mysql_execute_command (thd=thd@entry=0x7f5d58000d58, is_called_from_prepared_stmt=false) at /kvm/src/my/dev/mariadb3/sql/sql_parse.cc:4424

#24 0x000055cfddc43f3f in mysql_parse (thd=thd@entry=0x7f5d58000d58, rawbuf=<optimized out>, length=24, parser_state=parser_state@entry=0x7f5d82949360) at /kvm/src/my/dev/mariadb3/sql/sql_parse.cc:7905

#25 0x000055cfddc4211d in dispatch_command (command=command@entry=COM_QUERY, thd=thd@entry=0x7f5d58000d58, packet=packet@entry=0x7f5d58248319 "DELETE FROM t1 WHERE a=3", packet_length=packet_length@entry=24, blocking=true) at /kvm/src/my/dev/mariadb3/sql/sql_parse.cc:1903

Thread 4 (Thread 0x7f5d828ff6c0 (LWP 1795469)):

#9  0x000055cfdddc0e30 in inline_mysql_cond_timedwait (that=0x7f5d4c000f60, mutex=0x7f5d4c000eb0, abstime=0x7f5d828f9268, src_line=1211, src_file=<optimized out>) at /kvm/src/my/dev/mariadb3/include/mysql/psi/mysql_thread.h:1086

#10 MDL_wait::timed_wait (this=this@entry=0x7f5d4c000eb0, owner=0x7f5d4c000e40, abs_timeout=abs_timeout@entry=0x7f5d828f9268, set_status_on_timeout=false, wait_state_name=<optimized out>) at /kvm/src/my/dev/mariadb3/sql/mdl.cc:1210

#11 0x000055cfdddc2a1a in MDL_context::acquire_lock (this=this@entry=0x7f5d4c000eb0, mdl_request=mdl_request@entry=0x7f5d828f9340, lock_wait_timeout=lock_wait_timeout@entry=86400) at /kvm/src/my/dev/mariadb3/sql/mdl.cc:2441

#12 0x000055cfdddc3447 in MDL_context::upgrade_shared_lock (this=0x7f5d4c000eb0, mdl_ticket=0x7f5d4c01f7f0, new_type=MDL_SHARED_NO_WRITE, lock_wait_timeout=<error reading variable: Value cannot be represented as integer of 8 bytes.>) at /kvm/src/my/dev/mariadb3/sql/mdl.cc:2649

#13 0x000055cfddd33d24 in copy_data_between_tables (thd=thd@entry=0x7f5d4c000d58, from=0x7f5d4c0231a8, to=to@entry=0x7f5d4c027b28, ignore=true, order_num=<optimized out>, order=<optimized out>, copied=<optimized out>, deleted=<optimized out>, alter_info=<optimized out>, alter_ctx=<optimized out>, online=true, start_alter_id=<optimized out>) at /kvm/src/my/dev/mariadb3/sql/sql_table.cc:12999

#14 0x000055cfddd2bf5c in mysql_alter_table (thd=thd@entry=0x7f5d4c000d58, new_db=<optimized out>, new_name=<optimized out>, create_info=<optimized out>, table_list=0x7f5d4c015468, recreate_info=<optimized out>, recreate_info@entry=0x7f5d828fd590, alter_info=<optimized out>, order_num=<optimized out>, order=<optimized out>, ignore=<optimized out>, if_exists=<optimized out>) at /kvm/src/my/dev/mariadb3/sql/sql_table.cc:11921

#15 0x000055cfddd354dc in mysql_recreate_table (thd=thd@entry=0x7f5d4c000d58, table_list=table_list@entry=0x7f5d4c015468, recreate_info=recreate_info@entry=0x7f5d828fd590, table_copy=true) at /kvm/src/my/dev/mariadb3/sql/sql_table.cc:13138

#16 0x000055cfdddc9d7a in admin_recreate_table (thd=thd@entry=0x7f5d4c000d58, table_list=table_list@entry=0x7f5d4c015468, recreate_info=recreate_info@entry=0x7f5d828fd590, table_copy=true) at /kvm/src/my/dev/mariadb3/sql/sql_admin.cc:77

#17 0x000055cfdddc82e6 in mysql_admin_table (thd=thd@entry=0x7f5d4c000d58, tables=tables@entry=0x7f5d4c015468, check_opt=check_opt@entry=0x7f5d4c0065c0, operator_name=0x55cfdf072518 <msg_repair>, lock_type=lock_type@entry=TL_WRITE, org_open_for_modify=true, no_errors_from_open=<optimized out>, extra_open_options=<optimized out>, prepare_func=<optimized out>, operator_func=(int (handler::*)(handler * const, THD *, HA_CHECK_OPT *)) 0x55cfddf44e00 <handler::ha_repair(THD*, st_ha_check_opt*)>, view_operator_func=<optimized out>, is_cmd_replicated=<optimized out>) at /kvm/src/my/dev/mariadb3/sql/sql_admin.cc:1124

#18 0x000055cfdddc90de in Sql_cmd_repair_table::execute (this=<optimized out>, thd=0x7f5d4c000d58) at /kvm/src/my/dev/mariadb3/sql/sql_admin.cc:1701

#19 0x000055cfddc48473 in mysql_execute_command (thd=thd@entry=0x7f5d4c000d58, is_called_from_prepared_stmt=false) at /kvm/src/my/dev/mariadb3/sql/sql_parse.cc:5882

#20 0x000055cfddc43f3f in mysql_parse (thd=thd@entry=0x7f5d4c000d58, rawbuf=<optimized out>, length=15, parser_state=parser_state@entry=0x7f5d828fe360) at /kvm/src/my/dev/mariadb3/sql/sql_parse.cc:7905

#21 0x000055cfddc4211d in dispatch_command (command=command@entry=COM_QUERY, thd=thd@entry=0x7f5d4c000d58, packet=packet@entry=0x7f5d4c00acb9 "", packet_length=packet_length@entry=15, blocking=true) at /kvm/src/my/dev/mariadb3/sql/sql_parse.cc:1903