static int futex_lock_pi(u32 __user *uaddr, unsigned int flags,
			 ktime_t *time, int trylock)
{
	struct hrtimer_sleeper timeout, *to = NULL;
	struct futex_pi_state *pi_state = NULL;
	struct rt_mutex_waiter rt_waiter;
	struct futex_hash_bucket *hb;
	struct futex_q q = futex_q_init;
	int res, ret;

	if (!IS_ENABLED(CONFIG_FUTEX_PI))
		return -ENOSYS;

	if (refill_pi_state_cache())
		return -ENOMEM;

	if (time) {
		to = &timeout;
		hrtimer_init_on_stack(&to->timer, CLOCK_REALTIME,
				      HRTIMER_MODE_ABS);
		hrtimer_init_sleeper(to, current);
		hrtimer_set_expires(&to->timer, *time);
	}

retry:
	ret = get_futex_key(uaddr, flags & FLAGS_SHARED, &q.key, VERIFY_WRITE);
	if (unlikely(ret != 0))
		goto out;

retry_private:
	hb = queue_lock(&q);

	ret = futex_lock_pi_atomic(uaddr, hb, &q.key, &q.pi_state, current, 0);
	if (unlikely(ret)) {
		/*
		 * Atomic work succeeded and we got the lock,
		 * or failed. Either way, we do _not_ block.
		 */
		switch (ret) {
		case 1:
			/* We got the lock. */
			ret = 0;
			goto out_unlock_put_key;
		case -EFAULT:
			goto uaddr_faulted;
		case -EAGAIN:
			/*
			 * Two reasons for this:
			 * - Task is exiting and we just wait for the
			 *   exit to complete.
			 * - The user space value changed.
			 */
			queue_unlock(hb);
			put_futex_key(&q.key);
			cond_resched();
			goto retry;
		default:
			goto out_unlock_put_key;
		}
	}

	WARN_ON(!q.pi_state);

	/*
	 * Only actually queue now that the atomic ops are done:
	 */
	__queue_me(&q, hb);

	if (trylock) {
		ret = rt_mutex_futex_trylock(&q.pi_state->pi_mutex);
		/* Fixup the trylock return value: */
		ret = ret ? 0 : -EWOULDBLOCK;
		goto no_block;
	}

	rt_mutex_init_waiter(&rt_waiter);

	/*
	 * On PREEMPT_RT_FULL, when hb->lock becomes an rt_mutex, we must not
	 * hold it while doing rt_mutex_start_proxy(), because then it will
	 * include hb->lock in the blocking chain, even through we'll not in
	 * fact hold it while blocking. This will lead it to report -EDEADLK
	 * and BUG when futex_unlock_pi() interleaves with this.
	 *
	 * Therefore acquire wait_lock while holding hb->lock, but drop the
	 * latter before calling rt_mutex_start_proxy_lock(). This still fully
	 * serializes against futex_unlock_pi() as that does the exact same
	 * lock handoff sequence.
	 */
	raw_spin_lock_irq(&q.pi_state->pi_mutex.wait_lock);
	spin_unlock(q.lock_ptr);
	ret = __rt_mutex_start_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter, current);
	raw_spin_unlock_irq(&q.pi_state->pi_mutex.wait_lock);

	if (ret) {
		if (ret == 1)
			ret = 0;

		spin_lock(q.lock_ptr);
		goto no_block;
	}


	if (unlikely(to))
		hrtimer_start_expires(&to->timer, HRTIMER_MODE_ABS);

	ret = rt_mutex_wait_proxy_lock(&q.pi_state->pi_mutex, to, &rt_waiter);

	spin_lock(q.lock_ptr);
	/*
	 * If we failed to acquire the lock (signal/timeout), we must
	 * first acquire the hb->lock before removing the lock from the
	 * rt_mutex waitqueue, such that we can keep the hb and rt_mutex
	 * wait lists consistent.
	 *
	 * In particular; it is important that futex_unlock_pi() can not
	 * observe this inconsistency.
	 */
	if (ret && !rt_mutex_cleanup_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter))
		ret = 0;

no_block:
	/*
	 * Fixup the pi_state owner and possibly acquire the lock if we
	 * haven't already.
	 */
	res = fixup_owner(uaddr, &q, !ret);
	/*
	 * If fixup_owner() returned an error, proprogate that.  If it acquired
	 * the lock, clear our -ETIMEDOUT or -EINTR.
	 */
	if (res)
		ret = (res < 0) ? res : 0;

	/*
	 * If fixup_owner() faulted and was unable to handle the fault, unlock
	 * it and return the fault to userspace.
	 */
	if (ret && (rt_mutex_owner(&q.pi_state->pi_mutex) == current)) {
		pi_state = q.pi_state;
		get_pi_state(pi_state);
	}

	/* Unqueue and drop the lock */
	unqueue_me_pi(&q);

	if (pi_state) {
		rt_mutex_futex_unlock(&pi_state->pi_mutex);
		put_pi_state(pi_state);
	}

	goto out_put_key;

out_unlock_put_key:
	queue_unlock(hb);

out_put_key:
	put_futex_key(&q.key);
out:
	if (to) {
		hrtimer_cancel(&to->timer);
		destroy_hrtimer_on_stack(&to->timer);
	}
	return ret != -EINTR ? ret : -ERESTARTNOINTR;

uaddr_faulted:
	queue_unlock(hb);

	ret = fault_in_user_writeable(uaddr);
	if (ret)
		goto out_put_key;

	if (!(flags & FLAGS_SHARED))
		goto retry_private;

	put_futex_key(&q.key);
	goto retry;
}

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.