static int special_mapping_mremap(struct vm_area_struct *new_vma)
{
	struct vm_special_mapping *sm = new_vma->vm_private_data;

	if (WARN_ON_ONCE(current->mm != new_vma->vm_mm))
		return -EFAULT;

	if (sm->mremap)
		return sm->mremap(sm, new_vma);

	return 0;
}

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.