struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id)
{
	struct kern_ipc_perm *out;

	rcu_read_lock();
	out = ipc_obtain_object(ids, id);
	if (IS_ERR(out))
		goto err1;

	spin_lock(&out->lock);

	/* ipc_rmid() may have already freed the ID while ipc_lock
	 * was spinning: here verify that the structure is still valid
	 */
	if (!out->deleted)
		return out;

	spin_unlock(&out->lock);
	out = ERR_PTR(-EINVAL);
err1:
	rcu_read_unlock();
	return out;
}

This weakness involves numeric computation errors, such as integer overflows, underflows, or precision losses, which can lead to miscalculations and exploitable behaviors in software.