mariadb crashes when converting a large table to innodb

[ 5623.361638] mariadbd[3596]: segfault at fffffffffffffffd ip 000055a847115d2b sp 00007f3b75630570 error 5 in mariadbd[55a846472000+158c000]

[ 5623.361650] Code: 87 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 55 48 89 e5 41 57 41 56 41 55 41 54 49 89 f4 53 48 89 fb 48 83 ec 28 48 8b 76 18 <0f> b6 47 fd f6 46 40 01 74 23 83 e0 07 3c 04 0f 87 cd 06 00 00 48

CREATE TABLE `shortxxx` (

  `zzz` bigint(20) unsigned NOT NULL,

  `xxx` int(11) unsigned DEFAULT NULL,

  PRIMARY KEY (`zzz`),

  KEY `IDX_shortxxx_xxx` (`xxx`)

) ENGINE=ROCKSDB DEFAULT CHARSET=latin1 AVG_ROW_LENGTH=12 ROW_FORMAT=FIXED

innodb_adaptive_flushing = 1

innodb_adaptive_hash_index=1

innodb_buffer_pool_dump_at_shutdown=OFF

innodb_buffer_pool_load_at_startup=OFF

innodb_buffer_pool_size=20G

innodb_compression_algorithm=zlib

innodb_compression_level=6

innodb_doublewrite=0

innodb_file_per_table=1

innodb_flush_log_at_timeout=10

innodb_flush_log_at_trx_commit=0

innodb_flush_method=O_DIRECT_NO_FSYNC

innodb_flush_neighbors = 0

innodb_force_recovery=0

innodb_io_capacity=5000

innodb_io_capacity_max=10000

innodb_log_buffer_size=64M

innodb_lru_scan_depth=1024

innodb_max_dirty_pages_pct=90

innodb_open_files=4000

innodb_page_size=4096

innodb_purge_threads=4

innodb_read_io_threads = 64

innodb_stats_persistent = 1

innodb_strict_mode=0

innodb_thread_concurrency=0

innodb_use_atomic_writes=1

innodb_use_native_aio=1

innodb_write_io_threads = 64

connect_timeout=200

datadir=/var/lib/mysql

default-storage-engine = rocksdb

event_scheduler = 1

extra_max_connections=10

extra_port=9433

general-log-file=queries.log

general-log=0

general_log_file=mariadb.log

interactive_timeout=3000000

join_buffer_size=256K

join_buffer_size=8M

large_pages=1

log-output=file

log_error=/var/lib/mysql/mariadb.err

log_output='FILE'

log_warnings= 0

lower_case_table_names=1

max_allowed-packet=1G

max_connections=5000

max_heap_table_size=72M

memlock=1

net_read_timeout=2000

net_write_timeout=2000

open_files_limit=65535

plugin-load-add=ha_rocksdb.so

plugin_load_add = ha_blackhole

port =3306 

query_cache_size=0

query_cache_type=0

skip-innodb=0

skip_name_resolve=1

slave_load_tmpdir=/data/temp

slave_net_timeout=3600

socket=/var/lib/mysql/mysql.sock

sort_buffer_size=256K

sort_buffer_size=8M

symbolic_links=0

table_open_cache=3000

table_open_cache_instances=24

thread-pool-size=32

thread_cache_size=256

thread_handling=pool-of-threads

thread_stack=192K

tmp_table_size=64M

tmpdir=/large/temp

wait_timeout=6000

rocksdb-table-stats-sampling-pct=15

rocksdb_allow_concurrent_memtable_write=1

rocksdb_blind_delete_primary_key=1

rocksdb_block_cache_size=25G

rocksdb_block_size=16384

rocksdb_bulk_load_allow_unsorted=1

rocksdb_bulk_load_size=10000

rocksdb_bytes_per_sync=16777216

rocksdb_commit_in_the_middle=1

rocksdb_compaction_readahead_size=16m

rocksdb_compaction_sequential_deletes=199999

rocksdb_compaction_sequential_deletes_count_sd=1

rocksdb_compaction_sequential_deletes_window=200000

rocksdb_default_cf_options=write_buffer_size=256m;target_file_size_base=64m;max_bytes_for_level_base=512m;level0_file_num_compaction_trigger=4;level0_slowdown_writes_trigger=256;level0_stop_writes_trigger=256;max_write_buffer_number=16;compression_per_level=kNoCompression:kNoCompression:kNoCompression:kZlibCompression:kZlibCompression:kZlibCompression;bottommost_compression=kZlibCompression;compression_opts=-14:1:0;block_based_table_factory={cache_index_and_filter_blocks=1;filter_policy=bloomfilter:10:false;whole_key_filtering=1};level_compaction_dynamic_level_bytes=true;optimize_filters_for_hits=true

rocksdb_enable_ttl=1

rocksdb_flush_log_at_trx_commit=2

rocksdb_max_background_jobs=24

rocksdb_max_open_files=-1

rocksdb_max_row_locks=1073741824

rocksdb_max_subcompactions=16

rocksdb_max_total_wal_size=14G

rocksdb_strict_collation_check=off

rocksdb_table_cache_numshardbits=19

rocksdb_tmpdir=/data/temp

rocksdb_use_direct_io_for_flush_and_compaction=ON

rocksdb_use_direct_reads=OFF

rocksdb_wal_bytes_per_sync=4194304

rocksdb_write_disable_wal=1