obj: object header is no longer allocated automatically

sched/task.c

@@ -6,6 +6,8 @@
 #include <socks/cpu.h>
 #include <socks/libc/stdio.h>
 
+#define TASK_CAST(p) OBJECT_C_CAST(struct task, t_base, &task_type, p)
+
 static struct object_type task_type = {
 	.ob_name = "task",
 	.ob_size = sizeof(struct task),
@@ -144,7 +146,7 @@ struct task *task_alloc(void)
 		return NULL;
 	}
 
-	struct task *t = object_data(task_obj);
+	struct task *t = TASK_CAST(task_obj);
 	memset(t, 0x00, sizeof *t);
 	return t;
 }