static int uvesafb_exec(struct uvesafb_ktask *task)
{
	static int seq;
	struct cn_msg *m;
	int err;
	int len = sizeof(task->t) + task->t.buf_len;

	/*
	 * Check whether the message isn't longer than the maximum
	 * allowed by connector.
	 */
	if (sizeof(*m) + len > CONNECTOR_MAX_MSG_SIZE) {
		pr_warn("message too long (%d), can't execute task\n",
			(int)(sizeof(*m) + len));
		return -E2BIG;
	}

	m = kzalloc(sizeof(*m) + len, GFP_KERNEL);
	if (!m)
		return -ENOMEM;

	init_completion(task->done);

	memcpy(&m->id, &uvesafb_cn_id, sizeof(m->id));
	m->seq = seq;
	m->len = len;
	m->ack = prandom_u32();

	/* uvesafb_task structure */
	memcpy(m + 1, &task->t, sizeof(task->t));

	/* Buffer */
	memcpy((u8 *)(m + 1) + sizeof(task->t), task->buf, task->t.buf_len);

	/*
	 * Save the message ack number so that we can find the kernel
	 * part of this task when a reply is received from userspace.
	 */
	task->ack = m->ack;

	mutex_lock(&uvfb_lock);

	/* If all slots are taken -- bail out. */
	if (uvfb_tasks[seq]) {
		mutex_unlock(&uvfb_lock);
		err = -EBUSY;
		goto out;
	}

	/* Save a pointer to the kernel part of the task struct. */
	uvfb_tasks[seq] = task;
	mutex_unlock(&uvfb_lock);

	err = cn_netlink_send(m, 0, 0, GFP_KERNEL);
	if (err == -ESRCH) {
		/*
		 * Try to start the userspace helper if sending
		 * the request failed the first time.
		 */
		err = uvesafb_helper_start();
		if (err) {
			pr_err("failed to execute %s\n", v86d_path);
			pr_err("make sure that the v86d helper is installed and executable\n");
		} else {
			v86d_started = 1;
			err = cn_netlink_send(m, 0, 0, gfp_any());
			if (err == -ENOBUFS)
				err = 0;
		}
	} else if (err == -ENOBUFS)
		err = 0;

	if (!err && !(task->t.flags & TF_EXIT))
		err = !wait_for_completion_timeout(task->done,
				msecs_to_jiffies(UVESAFB_TIMEOUT));

	mutex_lock(&uvfb_lock);
	uvfb_tasks[seq] = NULL;
	mutex_unlock(&uvfb_lock);

	seq++;
	if (seq >= UVESAFB_TASKS_MAX)
		seq = 0;
out:
	kfree(m);
	return err;
}

The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.