Hotfix for mavlink logbuffer, needs another round of validation.

src/modules/mavlink/mavlink.c

@@ -516,7 +516,7 @@ void mavlink_update_system(void)
 int mavlink_thread_main(int argc, char *argv[])
 {
 	/* initialize mavlink text message buffering */
-	mavlink_logbuffer_init(&lb, 5);
+	mavlink_logbuffer_init(&lb, 2);
 
 	int ch;
 	char *device_name = "/dev/ttyS1";
@@ -738,6 +738,9 @@ int mavlink_thread_main(int argc, char *argv[])
 	/* Reset the UART flags to original state */
 	tcsetattr(uart, TCSANOW, &uart_config_original);
 
+	/* destroy log buffer */
+	mavlink_logbuffer_destroy(&lb);
+
 	thread_running = false;
 
 	exit(0);

src/modules/systemlib/mavlink_log.c

@@ -54,6 +54,14 @@ __EXPORT void mavlink_logbuffer_init(struct mavlink_logbuffer *lb, int size)
 	lb->elems = (struct mavlink_logmessage *)calloc(lb->size, sizeof(struct mavlink_logmessage));
 }
 
+__EXPORT void mavlink_logbuffer_destroy(struct mavlink_logbuffer *lb)
+{
+	lb->size  = 0;
+	lb->start = 0;
+	lb->count = 0;
+	free(lb->elems);
+}
+
 __EXPORT int mavlink_logbuffer_is_full(struct mavlink_logbuffer *lb)
 {
 	return lb->count == (int)lb->size;