static int keyctl_change_reqkey_auth(struct key *key)
{
	struct cred *new;

	new = prepare_creds();
	if (!new)
		return -ENOMEM;

	key_put(new->request_key_auth);
	new->request_key_auth = key_get(key);

	return commit_creds(new);
}

The product contains a concurrent code sequence that 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 operating concurrently.