SIGSEGV in ha_partition::create_partitioning_metadata on ALTER

USE test;

SET default_storage_engine=MyISAM;

SET SESSION alter_algorithm=4;

CREATE TABLE t(a INT) PARTITION BY RANGE(a) SUBPARTITION BY KEY(a) (PARTITION p0 VALUES LESS THAN (10) (SUBPARTITION s0,SUBPARTITION s1), PARTITION p1 VALUES LESS THAN (20) (SUBPARTITION s2,SUBPARTITION s3));

ALTER TABLE t ADD COLUMN c INT;

Core was generated by `/test/MD160520-mariadb-10.5.4-linux-x86_64-opt/bin/mysqld --no-defaults --core-'.

Program terminated with signal SIGSEGV, Segmentation fault.

#0  __pthread_kill (threadid=<optimized out>, signo=signo@entry=11)

    at ../sysdeps/unix/sysv/linux/pthread_kill.c:57

[Current thread is 1 (Thread 0x15319f35b700 (LWP 3223198))]

(gdb) bt

#0  __pthread_kill (threadid=<optimized out>, signo=signo@entry=11) at ../sysdeps/unix/sysv/linux/pthread_kill.c:57

#1  0x00005614731a9617 in my_write_core (sig=sig@entry=11) at /test/10.5_opt/mysys/stacktrace.c:518

#2  0x0000561472b6c0fa in handle_fatal_signal (sig=11) at /test/10.5_opt/sql/signal_handler.cc:329

#3  <signal handler called>

#4  0x0000561472dc6869 in ha_partition::create_partitioning_metadata (this=0x15317c46f630, path=0x15319f35928d "./test/#sql-alter-312c43-4", old_path=0x0, action_flag=CHF_DELETE_FLAG) at /test/10.5_opt/sql/ha_partition.cc:689

#5  0x00005614728677a3 in cleanup_table_after_inplace_alter (table=table@entry=0x15319f356730) at /test/10.5_opt/sql/sql_table.cc:9559

#6  0x0000561472a0e5de in mysql_alter_table (thd=thd@entry=0x15317c412018, new_db=new_db@entry=0x15317c416710, new_name=new_name@entry=0x15317c416b18, create_info=create_info@entry=0x15319f359600, table_list=<optimized out>, table_list@entry=0x15317c447118, alter_info=alter_info@entry=0x15319f359530, order_num=0, order=0x0, ignore=false, if_exists=false) at /test/10.5_opt/sql/sql_table.cc:10417

#7  0x0000561472a6a7a1 in Sql_cmd_alter_table::execute (this=<optimized out>, thd=0x15317c412018) at /test/10.5_opt/sql/sql_alter.cc:532

#8  0x00005614729765d0 in mysql_execute_command (thd=thd@entry=0x15317c412018) at /test/10.5_opt/sql/sql_parse.cc:5912

#9  0x000056147297d82c in mysql_parse (thd=0x15317c412018, rawbuf=<optimized out>, length=30, parser_state=0x15319f35a4b0, is_com_multi=<optimized out>, is_next_command=<optimized out>) at /test/10.5_opt/sql/sql_parse.cc:7957

#10 0x0000561472972e75 in dispatch_command (command=command@entry=COM_QUERY, thd=thd@entry=0x15317c412018, packet=packet@entry=0x15317c43a019 "ALTER TABLE t ADD COLUMN c INT", packet_length=packet_length@entry=30, is_com_multi=is_com_multi@entry=false, is_next_command=is_next_command@entry=false) at /test/10.5_opt/sql/sql_parse.cc:1839

#11 0x0000561472971106 in do_command (thd=0x15317c412018) at /test/10.5_opt/sql/sql_parse.cc:1358

#12 0x0000561472a65bf1 in do_handle_one_connection (connect=<optimized out>, connect@entry=0x15319d0329b8, put_in_cache=put_in_cache@entry=true) at /test/10.5_opt/sql/sql_connect.cc:1411

#13 0x0000561472a65f54 in handle_one_connection (arg=arg@entry=0x15319d0329b8) at /test/10.5_opt/sql/sql_connect.cc:1313

#14 0x0000561472dd143a in pfs_spawn_thread (arg=0x15319d04b018) at /test/10.5_opt/storage/perfschema/pfs.cc:2201

#15 0x000015319e7826db in start_thread (arg=0x15319f35b700) at pthread_create.c:463

#16 0x000015319db8088f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95