static int vop_mmap(struct file *f, struct vm_area_struct *vma)
{
	struct vop_vdev *vdev = f->private_data;
	unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
	unsigned long pa, size = vma->vm_end - vma->vm_start, size_rem = size;
	int i, err;

	err = vop_vdev_inited(vdev);
	if (err)
		goto ret;
	if (vma->vm_flags & VM_WRITE) {
		err = -EACCES;
		goto ret;
	}
	while (size_rem) {
		i = vop_query_offset(vdev, offset, &size, &pa);
		if (i < 0) {
			err = -EINVAL;
			goto ret;
		}
		err = remap_pfn_range(vma, vma->vm_start + offset,
				      pa >> PAGE_SHIFT, size,
				      vma->vm_page_prot);
		if (err)
			goto ret;
		size_rem -= size;
		offset += size;
	}
ret:
	return err;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.