Memory leak - mroonga/wrapper.temporary_table mroonga/wrapper.variable_match_escalation_threshold_session

$ mysql-test/mtr --no-reorder --parallel=1 mroonga/wrapper.temporary_table mroonga/wrapper.variable_match_escalation_threshold_session

results in:

=================================================================

==23304==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 40 byte(s) in 1 object(s) allocated from:

    #0 0x563c2b4f82b8 in malloc (/build/sql/mariadbd+0x15232b8) (BuildId: ae010aec0f9b1851e73b147824990600ed39f58d)

    #1 0x7b717b2a5202  (<unknown module>)

    #2 0x7b717b12ea6a  (<unknown module>)

    #3 0x7b717b5b8a34  (<unknown module>)

    #4 0x7b717b1f6472  (<unknown module>)

    #5 0x7b717ab03bfd  (<unknown module>)

    #6 0x7b717ab020d9  (<unknown module>)

    #7 0x7b717aa07feb  (<unknown module>)

    #8 0x563c2c21a450 in ha_initialize_handlerton(void*) /source/sql/handler.cc:654:37

    #9 0x563c2b98b637 in plugin_do_initialize(st_plugin_int*, unsigned int&) /source/sql/sql_plugin.cc:1457:18

    #10 0x563c2b98aa48 in plugin_initialize(st_mem_root*, st_plugin_int*, int*, char**, bool) /source/sql/sql_plugin.cc:1511:10

    #11 0x563c2b989e53 in plugin_init(int*, char**, int) /source/sql/sql_plugin.cc:1769:18

    #12 0x563c2b54c240 in init_server_components() /source/sql/mysqld.cc:5305:7

    #13 0x563c2b544565 in mysqld_main(int, char**) /source/sql/mysqld.cc:5955:7

    #14 0x7f71836b6ca7  (/lib/x86_64-linux-gnu/libc.so.6+0x29ca7) (BuildId: 58749c528985eab03e6700ebc1469fa50aa41219)

Objects leaked above:

0x7be619fe0990 (40 bytes)

(rr) break

Breakpoint 2 at 0x7ba6129ca4f0: file /source/storage/mroonga/vendor/groonga/lib/alloc.c, line 795.

(rr) clear 1

No breakpoint at 1.

(rr) delete 1

(rr) condition 2 $rax == 0x7be619fe0990

(rr) c

Continuing.

Thread 1 hit Breakpoint 2, 0x00007ba6129ca4f0 in grn_malloc_default (ctx=ctx@entry=0x7ba613529aa0 <mrn_ctx>, size=size@entry=40, file=<optimized out>, line=line@entry=1169, func=<optimized out>)

    at /source/storage/mroonga/vendor/groonga/lib/alloc.c:795

795	}

(rr) p/x $rax

$22 = 0x7be619fe0990

(rr) bt

#0  0x00007ba6129ca4f0 in grn_malloc_default (ctx=ctx@entry=0x7ba613529aa0 <mrn_ctx>, size=size@entry=40, file=<optimized out>, line=line@entry=1169, func=<optimized out>)

    at /source/storage/mroonga/vendor/groonga/lib/alloc.c:795

#1  0x00007ba612853a6b in grn_plugin_malloc (ctx=0x7be619fe0990, ctx@entry=0x7ba613529aa0 <mrn_ctx>, size=40, file=0x7be619fe0980 "\002\021", line=1169, func=0x0)

    at /source/storage/mroonga/vendor/groonga/lib/plugin.c:1074

#2  grn_plugin_mutex_open (ctx=0x7be619fe0990, ctx@entry=0x7ba613529aa0 <mrn_ctx>) at /source/storage/mroonga/vendor/groonga/lib/plugin.c:1169

#3  0x00007ba612cdda35 in grn_plugin_impl_init_tokenizers_mecab (ctx=<optimized out>) at /source/storage/mroonga/vendor/groonga/plugins/tokenizers/mecab.c:601

#4  0x00007ba61291b473 in grn_db_init_mecab_tokenizer (ctx=ctx@entry=0x7ba613529aa0 <mrn_ctx>) at /source/storage/mroonga/vendor/groonga/lib/tokenizers.c:772

#5  0x00007ba612228bfe in grn_db_init_builtin_types (ctx=0x7ba613529aa0 <mrn_ctx>) at /source/storage/mroonga/vendor/groonga/lib/db.c:12519

#6  0x00007ba6122270da in grn_db_create (ctx=0x7ba613529aa0 <mrn_ctx>, path=<optimized out>, optarg=<optimized out>) at /source/storage/mroonga/vendor/groonga/lib/db.c:275

#7  0x00007ba61212cfec in mrn_init (p=<optimized out>) at /source/storage/mroonga/ha_mroonga.cpp:1932

#8  0x000055bed4e2a451 in ha_initialize_handlerton (plugin_=0x7e3619ff6b78) at /source/sql/handler.cc:654

#9  0x000055bed459b638 in plugin_do_initialize (plugin=0x7e3619ff6b78, state=<optimized out>) at /source/sql/sql_plugin.cc:1457

#10 0x000055bed459aa49 in plugin_initialize (tmp_root=tmp_root@entry=0x7ba618ffe910, plugin=plugin@entry=0x7e3619ff6b78, argc=argc@entry=0x55bed8411700 <remaining_argc>, 

    argv=argv@entry=0x7db619fe3d78, options_only=<optimized out>) at /source/sql/sql_plugin.cc:1511

#11 0x000055bed4599e54 in plugin_init (argc=<optimized out>, argv=<optimized out>, flags=0) at /source/sql/sql_plugin.cc:1769

#12 0x000055bed415c241 in init_server_components () at /source/sql/mysqld.cc:5305

#13 0x000055bed4154566 in mysqld_main (argc=<optimized out>, argv=<optimized out>) at /source/sql/mysqld.cc:5955

#14 0x00007fa61b032ca8 in ?? () from /lib/x86_64-linux-gnu/libc.so.6

#15 0x00007fa61b032d65 in __libc_start_main () from /lib/x86_64-linux-gnu/libc.so.6

#16 0x000055bed40621f1 in _start ()

  sole_mecab_mutex = grn_plugin_mutex_open(ctx)