Valgrind Invalid read in tree_walk_left_root_right

$ perl ./mtr --valgrind main.func_gconcat

main.func_gconcat                        [ fail ]  Found warnings/errors in server log file!

        Test ended at 2019-12-22 01:18:43

line

==29619== Thread 6:

==29619== Invalid read of size 8

==29619==    at 0x4C32640: memmove (vg_replace_strmem.c:1252)

==29619==    by 0xEFAEAB: tree_insert (tree.c:255)

==29619==    by 0x8F8F62: copy_to_tree (item_sum.cc:3327)

==29619==    by 0xEFBB5A: tree_walk_left_root_right (tree.c:551)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==  Address 0xdc490c8 is 0 bytes after a block of size 296 alloc'd

==29619==    at 0x4C2BBAF: malloc (vg_replace_malloc.c:299)

==29619==    by 0xEE90BB: my_malloc (my_malloc.c:101)

==29619==    by 0xED9FC5: alloc_root (my_alloc.c:188)

==29619==    by 0xEFAE0D: tree_insert (tree.c:243)

==29619==    by 0x8F9531: Item_func_group_concat::add() (item_sum.cc:3416)

==29619==    by 0x8FAD3C: Aggregator_simple::add() (item_sum.h:672)

==29619==    by 0x668DAC: Item_sum::aggregator_add() (item_sum.h:521)

==29619==    by 0x668C97: Item_sum::reset_and_add() (item_sum.h:412)

==29619==    by 0x65F428: init_sum_functions(Item_sum**, Item_sum**) (sql_select.cc:23660)

==29619==    by 0x656247: end_send_group(JOIN*, st_join_table*, bool) (sql_select.cc:19927)

==29619==    by 0x65361B: evaluate_join_record(JOIN*, st_join_table*, int) (sql_select.cc:18812)

==29619==    by 0x652F0F: sub_select(JOIN*, st_join_table*, bool) (sql_select.cc:18589)

==29619==    by 0x652764: do_select(JOIN*, List<Item>*, TABLE*, Procedure*) (sql_select.cc:18244)

==29619==    by 0x62C2DD: JOIN::exec_inner() (sql_select.cc:3277)

==29619==    by 0x6295AA: JOIN::exec() (sql_select.cc:2564)

==29619==    by 0x62CB02: mysql_select(THD*, Item***, TABLE_LIST*, unsigned int, List<Item>&, Item*, unsigned int, st_order*, st_order*, Item*, st_order*, unsigned long long, select_result*, st_select_lex_unit*, st_select_lex*) (sql_select.cc:3501)

==29619== Invalid read of size 8

==29619==    at 0x4C3264E: memmove (vg_replace_strmem.c:1252)

==29619==    by 0xEFAEAB: tree_insert (tree.c:255)

==29619==    by 0x8F8F62: copy_to_tree (item_sum.cc:3327)

==29619==    by 0xEFBB5A: tree_walk_left_root_right (tree.c:551)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==  Address 0xe520330 is 0 bytes after a block of size 304 alloc'd

==29619==    at 0x4C2BBAF: malloc (vg_replace_malloc.c:299)

==29619==    by 0xEE90BB: my_malloc (my_malloc.c:101)

==29619==    by 0xED9FC5: alloc_root (my_alloc.c:188)

==29619==    by 0xEFAE0D: tree_insert (tree.c:243)

==29619==    by 0x8F8F62: copy_to_tree (item_sum.cc:3327)

==29619==    by 0xEFBB5A: tree_walk_left_root_right (tree.c:551)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)

==29619==    by 0xEFBB0B: tree_walk_left_root_right (tree.c:550)