static long ioctl_file_dedupe_range(struct file *file, void __user *arg)
{
	struct file_dedupe_range __user *argp = arg;
	struct file_dedupe_range *same = NULL;
	int ret;
	unsigned long size;
	u16 count;

	if (get_user(count, &argp->dest_count)) {
		ret = -EFAULT;
		goto out;
	}

	size = offsetof(struct file_dedupe_range __user, info[count]);

	same = memdup_user(argp, size);
	if (IS_ERR(same)) {
		ret = PTR_ERR(same);
		same = NULL;
		goto out;
	}

	same->dest_count = count;
	ret = vfs_dedupe_file_range(file, same);
	if (ret)
		goto out;

	ret = copy_to_user(argp, same, size);
	if (ret)
		ret = -EFAULT;

out:
	kfree(same);
	return ret;
}
The program contains a code sequence that can run concurrently with other code, and the code sequence 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 that is operating concurrently.