2019-11-16 15:25:57 0x2ad792405700  InnoDB: Assertion failure in file  /local/home/src/MariaDB/storage/innobase/page/page0page.cc line 863
InnoDB: Failing assertion: cur2
InnoDB: We intentionally generate a memory trap.
InnoDB: Submit a detailed bug report to https://jira.mariadb.org/
InnoDB: If you get repeated assertion failures or crashes, even
InnoDB: immediately after the mysqld startup, there may be
InnoDB: corruption in the InnoDB tablespace. Please refer to
InnoDB: https://mariadb.com/kb/en/library/xtradbinnodb-recovery-modes/
InnoDB: about forcing recovery.
191116 15:25:57 [ERROR] mysqld got signal 6 ;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.

To report this bug, see https://mariadb.com/kb/en/reporting-bugs

We will try our best to scrape up some info that will hopefully help
diagnose the problem, but since we have already crashed,
something is definitely wrong and this may fail.

Server version: 10.3.8-MariaDB-log
key_buffer_size=16777216
read_buffer_size=262144
max_used_connections=0
max_threads=1298
thread_count=4
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 3035955 K  bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x2ad78aa15308
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
2019-11-16 15:25:54 0 [Note] InnoDB: Mutexes and rw_locks use GCC atomic builtins
2019-11-16 15:25:54 0 [Note] InnoDB: Uses event mutexes
2019-11-16 15:25:54 0 [Note] InnoDB: Compressed tables use zlib 1.2.8
2019-11-16 15:25:54 0 [Note] InnoDB: Number of pools: 1
2019-11-16 15:25:54 0 [Note] InnoDB: Using SSE2 crc32 instructions
2019-11-16 15:25:54 0 [Note] InnoDB: Initializing buffer pool, total size = 11G, instances = 8, chunk size = 128M
2019-11-16 15:25:54 0 [Note] InnoDB: Completed initialization of buffer pool
2019-11-16 15:25:54 0 [Note] InnoDB: If the mysqld execution user is authorized, page cleaner thread priority can be changed. See the man page of setpriority().
2019-11-16 15:25:54 0 [Note] InnoDB: Starting crash recovery from checkpoint LSN=352105275656
2019-11-16 15:25:55 0 [Note] InnoDB: Starting final batch to recover 1209 pages from redo log.
2019-11-16 15:25:55 0 [Note] InnoDB: Last binlog file 'mysql-bin-changelog.000004', position 1065
2019-11-16 15:25:57 0 [Note] InnoDB: 128 out of 128 rollback segments are active.
2019-11-16 15:25:57 0 [Note] InnoDB: Removed temporary tablespace data file: "ibtmp1"
2019-11-16 15:25:57 0 [Note] InnoDB: Creating shared tablespace for temporary tables
2019-11-16 15:25:57 0 [Note] InnoDB: Setting file '/rdsdbdata/db/innodb/ibtmp1' size to 12 MB. Physically writing the file full; Please wait ...
2019-11-16 15:25:57 0 [Note] InnoDB: File '/rdsdbdata/db/innodb/ibtmp1' size is now 12 MB.
2019-11-16 15:25:57 0 [Note] InnoDB: Waiting for purge to start
2019-11-16 15:25:57 0x2ad792405700  InnoDB: Assertion failure in file  /local/home/src/MariaDB/storage/innobase/page/page0page.cc line 863
InnoDB: Failing assertion: cur2
InnoDB: We intentionally generate a memory trap.
InnoDB: Submit a detailed bug report to https://jira.mariadb.org/
InnoDB: If you get repeated assertion failures or crashes, even
InnoDB: immediately after the mysqld startup, there may be
InnoDB: corruption in the InnoDB tablespace. Please refer to
InnoDB: https://mariadb.com/kb/en/library/xtradbinnodb-recovery-modes/
InnoDB: about forcing recovery.
191116 15:25:57 [ERROR] mysqld got signal 6 ;
This could be because you hit a bug. It is also possible that this binary
or one of the libraries it was linked against is corrupt, improperly built,
or misconfigured. This error can also be caused by malfunctioning hardware.

To report this bug, see https://mariadb.com/kb/en/reporting-bugs

We will try our best to scrape up some info that will hopefully help
diagnose the problem, but since we have already crashed,
something is definitely wrong and this may fail.

Server version: 10.3.8-MariaDB-log
key_buffer_size=16777216
read_buffer_size=262144
max_used_connections=0
max_threads=1298
thread_count=4
It is possible that mysqld could use up to
key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 3035955 K  bytes of memory
Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x2ad78aa15308
Attempting backtrace. You can use the following information to find out
where mysqld died. If you see no messages after this, something went
terribly wrong...
stack_bottom = 0x2ad792404d98 thread_stack 0x40000
2019-11-16 15:25:57 0 [Note] InnoDB: 10.3.8 started; log sequence number 352120095434; transaction id 77477707
2019-11-16 15:25:57 0 [Note] InnoDB: Loading buffer pool(s) from /rdsdbdata/db/innodb/ib_buffer_pool
2019-11-16 15:25:57 0 [Note] Plugin 'FEEDBACK' is disabled.
2019-11-16 15:25:57 0 [Warning] /rdsdbbin/mysql/bin/mysqld: unknown variable 'loose-rocksdb_log_dir=/rdsdbdata/db/log'
2019-11-16 15:25:57 0 [Note] Recovering after a crash using /rdsdbdata/log/binlog/mysql-bin-changelog
2019-11-16 15:25:57 0 [Note] Starting crash recovery...
2019-11-16 15:25:57 0 [Note] Crash recovery finished.
2019-11-16 15:25:57 0 [Note] Server socket created on IP: '::'.
2019-11-16 15:25:57 0 [Note] Reading of all Master_info entries succeded
2019-11-16 15:25:57 0 [Note] Added new Master_info '' to hash table
2019-11-16 15:25:57 0 [Note] /rdsdbbin/mysql/bin/mysqld: ready for connections.
Version: '10.3.8-MariaDB-log'  socket: '/tmp/mysql.sock'  port: 3306  Source distribution
mysys/stacktrace.c:270(my_print_stacktrace)[0x5606f32e55f9]
sql/signal_handler.cc:165(handle_fatal_signal)[0x5606f2d785ed]
sigaction.c:0(__restore_rt)[0x2ad480e2e100]
:0(__GI_raise)[0x2ad4815885f7]
:0(__GI_abort)[0x2ad481589ce8]
ut/ut0rbt.cc:472(rbt_eject_node)[0x5606f2adc687]
page/page0page.cc:863(page_copy_rec_list_start(buf_block_t*, buf_block_t*, unsigned char*, dict_index_t*, mtr_t*))[0x5606f307dd28]
btr/btr0btr.cc:3905(btr_compress(btr_cur_t*, unsigned long, mtr_t*))[0x5606f315bff7]
btr/btr0cur.cc:5254(btr_cur_compress_if_useful(btr_cur_t*, unsigned long, mtr_t*))[0x5606f316907b]
btr/btr0cur.cc:5674(btr_cur_pessimistic_delete(dberr_t*, unsigned long, btr_cur_t*, unsigned long, bool, mtr_t*))[0x5606f316bbbf]
row/row0purge.cc:177(row_purge_remove_clust_if_poss_low)[0x5606f30d4f9d]
row/row0purge.cc:222(row_purge_remove_clust_if_poss)[0x5606f30d66d3]
row/row0purge.cc:1110(row_purge)[0x5606f30d7749]
que/que0que.cc:1046(que_thr_step)[0x5606f30942cd]
include/sync0types.h:1149(my_atomic_addlint)[0x5606f3121d81]
srv/srv0srv.cc:2585(srv_do_purge)[0x5606f3105cae]
pthread_create.c:0(start_thread)[0x2ad480e26dc5]
/lib64/libc.so.6(clone+0x6d)[0x2ad481649c9d]

Trying to get some variables.
Some pointers may be invalid and cause the dump to abort.
Query (0x0):
Connection ID (thread ID): 1
Status: NOT_KILLED

Optimizer switch: index_merge=on,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on

The manual page at http://dev.mysql.com/doc/mysql/en/crashing.html contains
information that should help you find out what is causing the crash.