check for dest being null

src/ucore_logging.c

@@ -170,6 +170,9 @@ void uc_log_add_destination(struct uc_log_destination *dest)
 {
     struct uc_log_destination *it;
 
+    if(dest == NULL)
+        return;
+
     pthread_mutex_lock(&log_lock);
 
     //make sure the destination isn't added twice.
@@ -204,6 +207,8 @@ static inline void uc_log_remove_dest_unlocked(struct uc_log_destination *dest)
 
 void uc_log_remove_destination(struct uc_log_destination *dest)
 {
+    if(dest == NULL)
+        return;
 
     pthread_mutex_lock(&log_lock);