160722 23:14:03 [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: 10.1.16-MariaDB-1~trusty

key_buffer_size=16777216

read_buffer_size=131072

max_used_connections=23

max_threads=502

thread_count=13

It is possible that mysqld could use up to 

key_buffer_size + (read_buffer_size + sort_buffer_size)*max_threads = 1118998 K  bytes of memory

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

Thread pointer: 0x0x7f57a83d6008

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 = 0x7f61375fedf0 thread_stack 0x80000

/usr/sbin/mysqld(my_print_stacktrace+0x2e)[0x7f65391b28fe]

/usr/sbin/mysqld(handle_fatal_signal+0x2d5)[0x7f6538cd9e75]

/lib/x86_64-linux-gnu/libpthread.so.0(+0x10330)[0x7f653722f330]

/usr/sbin/mysqld(+0x4812d4)[0x7f6538baa2d4]

/usr/sbin/mysqld(_ZN13st_select_lex5printEP3THDP6String15enum_query_type+0x4b2)[0x7f6538baac02]

/usr/sbin/mysqld(_ZN14Item_subselect5printEP6String15enum_query_type+0x5f)[0x7f6538d69faf]

/usr/sbin/mysqld(_ZN22Item_func_conv_charset5printEP6String15enum_query_type+0x44)[0x7f6538d57e64]

/usr/sbin/mysqld(_ZN9Item_func10print_argsEP6Stringj15enum_query_type+0x4f)[0x7f6538d3a9df]

/usr/sbin/mysqld(_ZN9Item_func5printEP6String15enum_query_type+0x4d)[0x7f6538d3aabd]

/usr/sbin/mysqld(_ZN9Item_func10print_argsEP6Stringj15enum_query_type+0x4f)[0x7f6538d3a9df]

/usr/sbin/mysqld(_ZN9Item_func5printEP6String15enum_query_type+0x4d)[0x7f6538d3aabd]

/usr/sbin/mysqld(_ZN4Item17print_item_w_nameEP6String15enum_query_type+0x1c)[0x7f6538cf0fdc]

/usr/sbin/mysqld(_ZN13st_select_lex5printEP3THDP6String15enum_query_type+0x226)[0x7f6538baa976]

/usr/sbin/mysqld(_ZN18st_select_lex_unit5printEP6String15enum_query_type+0x57)[0x7f6538b4c267]

/usr/sbin/mysqld(_Z29mysqld_show_create_get_fieldsP3THDP10TABLE_LISTP4ListI4ItemEP6String+0x302)[0x7f6538bb9eb2]

/usr/sbin/mysqld(_Z18mysqld_show_createP3THDP10TABLE_LIST+0xc0)[0x7f6538bba8e0]

/usr/sbin/mysqld(_Z21mysql_execute_commandP3THD+0x3fbc)[0x7f6538b5aecc]

/usr/sbin/mysqld(_Z11mysql_parseP3THDPcjP12Parser_state+0x26d)[0x7f6538b6073d]

/usr/sbin/mysqld(_Z16dispatch_command19enum_server_commandP3THDPcj+0x2460)[0x7f6538b63a80]

/usr/sbin/mysqld(_Z10do_commandP3THD+0x169)[0x7f6538b64239]

/usr/sbin/mysqld(_Z24do_handle_one_connectionP3THD+0x18a)[0x7f6538c2889a]

/usr/sbin/mysqld(handle_one_connection+0x40)[0x7f6538c28a70]

/lib/x86_64-linux-gnu/libpthread.so.0(+0x8184)[0x7f6537227184]

/lib/x86_64-linux-gnu/libc.so.6(clone+0x6d)[0x7f653674637d]

Trying to get some variables.

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

Query (0x7f57a70fe020): is an invalid pointer

Connection ID (thread ID): 478