static struct sk_buff *ath_tid_dequeue(struct ath_atx_tid *tid)
{
	struct sk_buff *skb;

	skb = __skb_dequeue(&tid->retry_q);
	if (!skb)
		skb = __skb_dequeue(&tid->buf_q);

	return skb;
}

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.