Assertion `mysql_socket.fd != -1' failed in mysql_socket.h upon KILL_SERVER

2019-02-22 10:25:19 0 [Warning] /home/vsts/server/bin/mysqld: Forcing close of thread 17  user: 'rqg'

2019-02-22 10:25:19 0 [Warning] /home/vsts/server/bin/mysqld: Forcing close of thread 16  user: 'rqg'

2019-02-22 10:25:19 0 [Warning] /home/vsts/server/bin/mysqld: Forcing close of thread 15  user: 'rqg'

mysqld: /home/vsts/src/include/mysql/psi/mysql_socket.h:738: inline_mysql_socket_send: Assertion `mysql_socket.fd != -1' failed.

190222 10:25:21 [ERROR] mysqld got signal 6 ;

#5  0x00007f87fc4cd02a in __GI_abort () at abort.c:89

#6  0x00007f87fc4c3bd7 in __assert_fail_base (fmt=<optimized out>, assertion=assertion@entry=0x555fef529460 "mysql_socket.fd != -1", file=file@entry=0x555fef529430 "/home/vsts/src/include/mysql/psi/mysql_socket.h", line=line@entry=738, function=function@entry=0x555fef529920 <__PRETTY_FUNCTION__.12480> "inline_mysql_socket_send") at assert.c:92

#7  0x00007f87fc4c3c82 in __GI___assert_fail (assertion=0x555fef529460 "mysql_socket.fd != -1", file=0x555fef529430 "/home/vsts/src/include/mysql/psi/mysql_socket.h", line=738, function=0x555fef529920 <__PRETTY_FUNCTION__.12480> "inline_mysql_socket_send") at assert.c:101

#8  0x0000555fef02da48 in inline_mysql_socket_send (src_file=0x555fef529478 "/home/vsts/src/vio/viosocket.c", src_line=298, mysql_socket=..., buf=0x7f87c800b300, n=74, flags=64) at /home/vsts/src/include/mysql/psi/mysql_socket.h:738

#9  0x0000555fef02e6ab in vio_write (vio=0x555ff2423b00, buf=0x7f87c800b300 "F", size=74) at /home/vsts/src/vio/viosocket.c:297

#10 0x0000555fee40a9d5 in net_real_write (net=0x7f87c8000ff8, packet=0x7f87c800b300 "F", len=74) at /home/vsts/src/sql/net_serv.cc:681

#11 0x0000555fee40a087 in net_flush (net=0x7f87c8000ff8) at /home/vsts/src/sql/net_serv.cc:383

#12 0x0000555fee40a4c2 in net_write_command (net=0x7f87c8000ff8, command=255 '\377', header=0x555fef06a740 "", head_len=0, packet=0x7f87f8ed81b0 "\261\a#70100Query execution was interrupted (max_statement_time exceeded)", len=69) at /home/vsts/src/sql/net_serv.cc:521

#13 0x0000555fee4117c2 in net_send_error_packet (thd=0x7f87c8000d10, sql_errno=1969, err=0x7f87c800629b "Query execution was interrupted (max_statement_time exceeded)", sqlstate=0x7f87c8006280 "70100") at /home/vsts/src/sql/protocol.cc:465

#14 0x0000555fee411e02 in Protocol::send_error (this=0x7f87c80012c8, sql_errno=1969, err_msg=0x7f87c800629b "Query execution was interrupted (max_statement_time exceeded)", sql_state=0x7f87c8006280 "70100") at /home/vsts/src/sql/protocol.cc:643

#15 0x0000555fee411ad5 in Protocol::end_statement (this=0x7f87c80012c8) at /home/vsts/src/sql/protocol.cc:569

#16 0x0000555fee51a382 in dispatch_command (command=COM_QUERY, thd=0x7f87c8000d10, packet=0x7f87c800b301 "", packet_length=89, is_com_multi=false, is_next_command=false) at /home/vsts/src/sql/sql_parse.cc:2411

#17 0x0000555fee517180 in do_command (thd=0x7f87c8000d10) at /home/vsts/src/sql/sql_parse.cc:1396

#18 0x0000555fee67f47b in do_handle_one_connection (connect=0x555ff18a5f80) at /home/vsts/src/sql/sql_connect.cc:1403

#19 0x0000555fee67f1cc in handle_one_connection (arg=0x555ff18a5f80) at /home/vsts/src/sql/sql_connect.cc:1309

#20 0x00007f87fd1086ba in start_thread (arg=0x7f87f8ed9700) at pthread_create.c:333

#21 0x00007f87fc59d41d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109

Query (0x7f87c8013ac8): LOAD DATA INFILE 'load_view_PP_J' REPLACE INTO TABLE view_PP_J /* QNO 1513 CON_ID 16 */

Connection ID (thread ID): 16

Status: KILL_SERVER