static void put_pi_state(struct futex_pi_state *pi_state)
{
	if (!pi_state)
		return;

	if (!atomic_dec_and_test(&pi_state->refcount))
		return;

	/*
	 * If pi_state->owner is NULL, the owner is most probably dying
	 * and has cleaned up the pi_state already
	 */
	if (pi_state->owner) {
		struct task_struct *owner;

		raw_spin_lock_irq(&pi_state->pi_mutex.wait_lock);
		owner = pi_state->owner;
		if (owner) {
			raw_spin_lock(&owner->pi_lock);
			list_del_init(&pi_state->list);
			raw_spin_unlock(&owner->pi_lock);
		}
		rt_mutex_proxy_unlock(&pi_state->pi_mutex, owner);
		raw_spin_unlock_irq(&pi_state->pi_mutex.wait_lock);
	}

	if (current->pi_state_cache) {
		kfree(pi_state);
	} else {
		/*
		 * pi_state->list is already empty.
		 * clear pi_state->owner.
		 * refcount is at 0 - put it back to 1.
		 */
		pi_state->owner = NULL;
		atomic_set(&pi_state->refcount, 1);
		current->pi_state_cache = pi_state;
	}
}

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.