set null to a few dangling pointers i forgot

src/lkby_discovery.c

@@ -146,13 +146,15 @@ static void read_keyboards(FILE *devices)
             if (NULL == (kb_name = retrieve_keyboard_name(dev))) {
                 free(kb_event);
                 free(dev);
-                dev = NULL;
+                dev      = NULL;
+                kb_event = NULL;
                 continue;
             }
             store_kb_to_transmit_queue((const char *) kb_event, 
                                        (const char *) kb_name);
         }
         free(dev);
+        dev = NULL;
     }
     // inform the scheduler thread that there are keyboards in the queue.
     (void)sem_post(&LKBYQUEUE_SEM(&g_keyboard_queue));

src/lkby_scheduler.c

@@ -84,7 +84,7 @@ static inline int add_active_kb(const struct active_kb *src)
  * @param src The keyboard to remove.
  * @return 0 on success, otherwise -1.
  **/
-static int remove_active_kb(struct active_kb *restrict src)
+static int remove_active_kb(struct active_kb *src)
 {
     int index = -1;
     for (size_t i = 0; i < g_active_next; i++) {
@@ -106,6 +106,7 @@ static int remove_active_kb(struct active_kb *restrict src)
     lkby_keyboard_free(&LKBYACTIVE_KB(src));
     // free the previous allocated active_keyboard.
     free(src);
+    src = NULL;
     --g_active_next;
 
     if (g_s_active_kbs - g_active_next > 10) {
@@ -230,6 +231,7 @@ static void *keyboard_routine(void *src)
 
 keyboard_routine_failed_label:
     free(absolute_path_to_event);
+    absolute_path_to_event = NULL;
     (void)close(event_fd);
     pthread_cleanup_pop(1);
     return NULL;
@@ -285,7 +287,6 @@ void *lkby_start_scheduler(void *none __attribute__((unused)))
             (void)pthread_detach(ac_kb->kb_thread);
 
             continue; // ! DO NOT GO TO THE ARREA OF ERRORS. (label below).
-            // TODO - this error handling need more tests.
 lkby_scheduler_failed_label:
             free(kb);
             free(ac_kb);