10.1.21 crash

170301  0:40:01 [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: 10.1.21-MariaDB

key_buffer_size=3221225472

read_buffer_size=6291456

max_used_connections=502

max_threads=602

thread_count=79

It is possible that mysqld could use up to 

key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 85762103 K  bytes of memory

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

Thread pointer: 0x7f6e58b00a38

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 = 0x7f67b2a2ccf0 thread_stack 0x30000

/usr/libexec/mysqld(my_print_stacktrace+0x2e)[0x7f6e565ce80e]

/usr/libexec/mysqld(handle_fatal_signal+0x305)[0x7f6e560f5da5]

/lib64/libpthread.so.0(+0xf370)[0x7f6e55712370]

/usr/libexec/mysqld(_ZN11Query_cache12move_by_typeEPPhPP17Query_cache_blockPmS3_+0x730)[0x7f6e55f3b920]

/usr/libexec/mysqld(_ZN11Query_cache10pack_cacheEv+0x71)[0x7f6e55f3bb21]

/usr/libexec/mysqld(_ZN11Query_cache4packEP3THDmj+0x4e)[0x7f6e55f3be0e]

/usr/libexec/mysqld(_Z20reload_acl_and_cacheP3THDyP10TABLE_LISTPi+0x690)[0x7f6e5605e970]

/usr/libexec/mysqld(_Z21mysql_execute_commandP3THD+0x1400)[0x7f6e55f716a0]

/usr/libexec/mysqld(_Z11mysql_parseP3THDPcjP12Parser_state+0x332)[0x7f6e55f79682]

/usr/libexec/mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0x243c)[0x7f6e55f7c99c]

/usr/libexec/mysqld(_Z10do_commandP3THD+0x14a)[0x7f6e55f7d1fa]

/usr/libexec/mysqld(_Z24do_handle_one_connectionP3THD+0x18a)[0x7f6e5604445a]

/usr/libexec/mysqld(handle_one_connection+0x40)[0x7f6e56044600]

/lib64/libpthread.so.0(+0x7dc5)[0x7f6e5570adc5]

/lib64/libc.so.6(clone+0x6d)[0x7f6e53f8373d]

Trying to get some variables.

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

Query (0x7f68c40008e0): FLUSH QUERY CACHE

Connection ID (thread ID): 568895

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=off