SHOW WARNINGS will SIGSEGV 10.5 optimized build after setting CHARACTER_SET_RESULTS to NULL and running any invalid SQL | Binary_string::copy_printable_hhhh

SET @@CHARACTER_SET_RESULTS=NULL;

a;

SHOW WARNINGS;

Core was generated by `/data/MD020420-mariadb-10.5.3-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 0x7f3885180700 (LWP 13873))]

(gdb) bt

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

#1  0x000055cf90ac0d47 in my_write_core (sig=sig@entry=11) at /data/10.5_opt/mysys/stacktrace.c:518

#2  0x000055cf9048287a in handle_fatal_signal (sig=11) at /data/10.5_opt/sql/signal_handler.cc:325

#3  <signal handler called>

#4  Binary_string::copy_printable_hhhh (this=this@entry=0x7f388517ec80, to_cs=0x0, from_cs=0x55cf91606400 <my_charset_utf8mb3_general_ci>, from=0x7f38558549c0 "You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near 'a' at line 1", from_length=from_length@entry=149) at /data/10.5_opt/sql/sql_string.cc:788

#5  0x000055cf901d6b14 in Protocol::store_warning (this=this@entry=0x7f3855812558, from=<optimized out>, length=length@entry=149) at /data/10.5_opt/sql/protocol.cc:1199

#6  0x000055cf90253050 in mysqld_show_warnings (thd=thd@entry=0x7f3855812018, levels_to_show=levels_to_show@entry=7) at /data/10.5_opt/sql/sql_error.cc:825

#7  0x000055cf9028df56 in mysql_execute_command (thd=thd@entry=0x7f3855812018) at /data/10.5_opt/sql/sql_parse.cc:3971

#8  0x000055cf90294a6c in mysql_parse (thd=thd@entry=0x7f3855812018, rawbuf=<optimized out>, length=13, parser_state=parser_state@entry=0x7f388517f4d0, is_com_multi=is_com_multi@entry=false, is_next_command=is_next_command@entry=false) at /data/10.5_opt/sql/sql_parse.cc:7953

#9  0x000055cf902898e0 in dispatch_command (command=command@entry=COM_QUERY, thd=thd@entry=0x7f3855812018, packet=packet@entry=0x7f385583a019 "", packet_length=packet_length@entry=13, is_com_multi=is_com_multi@entry=false, is_next_command=is_next_command@entry=false) at /data/10.5_opt/sql/sql_parse.cc:1839

#10 0x000055cf90287bff in do_command (thd=0x7f3855812018) at /data/10.5_opt/sql/sql_parse.cc:1358

#11 0x000055cf9037c92e in do_handle_one_connection (connect=<optimized out>, connect@entry=0x7f3882c329b8, put_in_cache=put_in_cache@entry=true) at /data/10.5_opt/sql/sql_connect.cc:1422

#12 0x000055cf9037cad4 in handle_one_connection (arg=arg@entry=0x7f3882c329b8) at /data/10.5_opt/sql/sql_connect.cc:1319

#13 0x000055cf906e89da in pfs_spawn_thread (arg=0x7f3882c4b018) at /data/10.5_opt/storage/perfschema/pfs.cc:2201

#14 0x00007f38845a76db in start_thread (arg=0x7f3885180700) at pthread_create.c:463

#15 0x00007f38839a588f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95