200804  5:05:51 [ERROR] mysqld got signal 11 ;

 ...

We think the query pointer is invalid, but we will try to print it anyway. 

Query: ALTER TABLE albums ADD CONSTRAINT albums_fk1 FOREIGN KEY(list_id) REFERENCES lists (id)

[mysqld]

#

# * Basic Settings

#

basedir		    = /usr

tmpdir	            = /tmp

skip-external-locking

character_set_server    = utf8

ignore_db_dirs          = lost+found

#

# * Fine Tuning

#

ft_min_word_len         = 3

join_buffer_size        = 131072

key_buffer_size         = 16M

max_allowed_packet      = 256M

#max_connections        = 100

max_heap_table_size     = 16M

query_cache_type        = OFF

query_cache_size        = 0

read_buffer_size        = 131072

read_rnd_buffer_size    = 262144

table_open_cache        = 4096

thread_stack            = 192K

thread_cache_size       = 8

#thread_concurrency     = 12

tmp_table_size          = 16M

interactive_timeout     = 28800

net_read_timeout        = 30

net_write_timeout       = 60

wait_timeout            = 3600

#

# * Slow query log

#

slow_query_log_file     = /var/log/mysql/mysql-slow.log

slow_query_log          = 1

long_query_time         = 4

#log_queries_not_using_indexes

#

# * InnoDB

#

innodb_data_file_path        = ibdata1:10M:autoextend

innodb_buffer_pool_instances = 1

innodb_buffer_pool_size      = 1024M

innodb_log_file_size         = 32M

200804  5:05:51 [ERROR] mysqld got signal 11 ;

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: 10.4.13-MariaDB-1:10.4.13+maria~buster-log

key_buffer_size=16777216

read_buffer_size=131072

max_used_connections=3

max_threads=153

thread_count=18

It is possible that mysqld could use up to 

key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 353068 K  bytes of memory

Hope that's ok; if not, decrease some variables in the equation.

Thread pointer: 0x7f6934000e78

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 = 0x7f69e40ccdd8 thread_stack 0x30000

/usr/sbin/mysqld(my_print_stacktrace+0x2e)[0x5627800f18de]

/usr/sbin/mysqld(handle_fatal_signal+0x54d)[0x56277fbe9c4d]

/lib/x86_64-linux-gnu/libpthread.so.0(+0x12730)[0x7f6a16239730]

Trying to get some variables.

Some pointers may be invalid and cause the dump to abort.

Query (0x7f6934010270): is an invalid pointer

Connection ID (thread ID): 160

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=on,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on,condition_pushdown_for_subquery=on,rowid_filter=on,condition_pushdown_from_having=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.

We think the query pointer is invalid, but we will try to print it anyway. 

Query: ALTER TABLE albums ADD CONSTRAINT albums_fk1 FOREIGN KEY(list_id) REFERENCES lists (id)

Writing a core file...

Working directory at /var/lib/mysql

Resource Limits:

Limit                     Soft Limit           Hard Limit           Units     

Max cpu time              unlimited            unlimited            seconds   

Max file size             unlimited            unlimited            bytes     

Max data size             unlimited            unlimited            bytes     

Max stack size            8388608              unlimited            bytes     

Max core file size        unlimited            unlimited            bytes     

Max resident set          unlimited            unlimited            bytes     

Max processes             unlimited            unlimited            processes 

Max open files            1048576              1048576              files     

Max locked memory         65536                65536                bytes     

Max address space         unlimited            unlimited            bytes     

Max file locks            unlimited            unlimited            locks     

Max pending signals       127370               127370               signals   

Max msgqueue size         819200               819200               bytes     

Max nice priority         0                    0                    

Max realtime priority     0                    0                    

Max realtime timeout      unlimited            unlimited            us        

Core pattern: |/usr/share/apport/apport %p %s %c %d %P ...