message: mark region as unsafe
diff: @@ -125,12 +125,14 @@ impl TaskStacks {
  );
  // clear user stack
  + unsafe {
  ptr::write_bytes(
  (virt_addr + KERNEL_STACK_SIZE + DEFAULT_STACK_SIZE + 3 * BasePageSize::SIZE)
  as *mut u8,
  0,
  user_stack_size,
  );
  + }
  TaskStacks::Common(CommonStack {
  virt_addr: virt_addr,
  