Fixes segfault related to accesses to 'GloMyLogger' and 'GloMTH' when are already deinitialized

lib/MySQL_HostGroups_Manager.cpp

@@ -182,6 +182,7 @@ static void gtid_async_cb(struct ev_loop *loop, struct ev_async *watcher, int re
 }
 
 static void gtid_timer_cb (struct ev_loop *loop, struct ev_timer *timer, int revents) {
+	if (GloMTH == nullptr) { return; }
 	ev_timer_stop(loop, timer);
 	ev_timer_set(timer, __sync_add_and_fetch(&GloMTH->variables.binlog_reader_connect_retry_msec,0)/1000, 0);
 	if (glovars.shutdown) {

lib/MySQL_Session.cpp

@@ -3331,7 +3331,7 @@ __get_pkts_from_client:
 								break;
 							case _MYSQL_COM_QUIT:
 								proxy_debug(PROXY_DEBUG_MYSQL_COM, 5, "Got COM_QUIT packet\n");
-								GloMyLogger->log_audit_entry(PROXYSQL_MYSQL_AUTH_QUIT, this, NULL);
+								if (GloMyLogger) { GloMyLogger->log_audit_entry(PROXYSQL_MYSQL_AUTH_QUIT, this, NULL); }
 								l_free(pkt.size,pkt.ptr);
 								handler_ret = -1;
 								return handler_ret;
@@ -3418,7 +3418,7 @@ __get_pkts_from_client:
 						c=*((unsigned char *)pkt.ptr+sizeof(mysql_hdr));
 						if (c==_MYSQL_COM_QUIT) {
 							proxy_error("Unexpected COM_QUIT from client %s . Session_status: %d , client_status: %d Disconnecting it\n", buf, status, client_myds->status);
-							GloMyLogger->log_audit_entry(PROXYSQL_MYSQL_AUTH_QUIT, this, NULL);
+							if (GloMyLogger) { GloMyLogger->log_audit_entry(PROXYSQL_MYSQL_AUTH_QUIT, this, NULL); }
 							proxy_debug(PROXY_DEBUG_MYSQL_COM, 5, "Got COM_QUIT packet\n");
 							l_free(pkt.size,pkt.ptr);
 							if (thread) {

lib/MySQL_Thread.cpp

@@ -3664,7 +3664,7 @@ MySQL_Thread::~MySQL_Thread() {
 				if (sess->session_type == PROXYSQL_SESSION_ADMIN || sess->session_type == PROXYSQL_SESSION_STATS) {
 					char _buf[1024];
 					sprintf(_buf,"%s:%d:%s()", __FILE__, __LINE__, __func__);
-					GloMyLogger->log_audit_entry(PROXYSQL_MYSQL_AUTH_CLOSE, sess, NULL, _buf);
+					if (GloMyLogger) { GloMyLogger->log_audit_entry(PROXYSQL_MYSQL_AUTH_CLOSE, sess, NULL, _buf); }
 				}
 				delete sess;
 			}