fix scheduling bug that was triggered when a single process available

PauloMigAlmeida · Dec 20, 2021 · 864a1e4 · 864a1e4
1 parent 704d2ba
commit 864a1e4
Showing 1 changed file with 7 additions and 5 deletions.
diff --git a/src/kernel/task/scheduler.c b/src/kernel/task/scheduler.c
@@ -50,7 +50,6 @@ static void move_end_of_list(struct task_list_t *element) {
 
     if (head->next == NULL) {
         head->next = element;
-        element->next = NULL;
     } else {
         struct task_list_t *tmp = this_rq()->tasks;
         /* find list's tail */
@@ -61,10 +60,10 @@ static void move_end_of_list(struct task_list_t *element) {
         }
 
         tmp->next = element;
-        this_rq()->tasks = element->next;
-        element->next = NULL;
     }
 
+    element->next = NULL;
+
 }
 
 void scheduler_add(task_struct_t *task) {
@@ -84,15 +83,18 @@ void schedule(interrupt_stack_frame_t *int_frame) {
     struct task_list_t *head = this_rq()->tasks;
 
     /* fail-fast if there is nothing else to run */
-    if ((this_rq()->curr != NULL && head->next == NULL) || head == NULL)
+    if (!head || (this_rq()->curr && !head->next))
         return;
 
     task_struct_t *curr = this_rq()->curr;
     task_struct_t *next = head->val;
 
     /* puts current process at the end of list to
      * give a change for the other tasks to run */
-    move_end_of_list(head);
+    if (head->next) {
+        this_rq()->tasks = head->next;
+        move_end_of_list(head);
+    }
 
     /* select process to be executed */
     this_rq()->curr = next;