sched: enforce ref-counting on current task/thread pointers

syscall/object.c

@@ -13,12 +13,13 @@ kern_status_t sys_kern_object_wait(kern_wait_item_t *items, size_t nr_items)
 		return KERN_INVALID_ARGUMENT;
 	}
 
-	struct task *self = current_task();
-	struct thread *self_thread = current_thread();
+	struct task *self = get_current_task();
 	if (!validate_access_rw(self, items, nr_items * sizeof *items)) {
+		put_current_task(self);
 		return KERN_MEMORY_FAULT;
 	}
 
+	struct thread *self_thread = get_current_thread();
 	self_thread->tr_state = THREAD_SLEEPING;
 
 	kern_status_t status = KERN_OK;
@@ -78,6 +79,9 @@ cleanup:
 	}
 
 	self_thread->tr_state = THREAD_READY;
+	put_current_thread(self_thread);
+	put_current_task(self);
+
 	return status;
 }
 
@@ -85,13 +89,15 @@ kern_status_t sys_kern_object_query(
 	kern_handle_t object_handle,
 	kern_object_info_t *out)
 {
-	struct task *self = current_task();
+	struct task *self = get_current_task();
 
 	if (!out) {
+		put_current_task(self);
 		return KERN_INVALID_ARGUMENT;
 	}
 
 	if (!validate_access_w(self, out, sizeof *out)) {
+		put_current_task(self);
 		return KERN_MEMORY_FAULT;
 	}
 
@@ -100,12 +106,14 @@ kern_status_t sys_kern_object_query(
 	kern_status_t status
 		= task_resolve_handle(self, object_handle, &obj, &flags);
 	if (status != KERN_OK) {
+		put_current_task(self);
 		return status;
 	}
 
 	out->obj_id = obj->ob_id;
 
 	object_unref(obj);
+	put_current_task(self);
 
 	return KERN_OK;
 }