static bool ath_lookup_legacy(struct ath_buf *bf)
{
	struct sk_buff *skb;
	struct ieee80211_tx_info *tx_info;
	struct ieee80211_tx_rate *rates;
	int i;

	skb = bf->bf_mpdu;
	tx_info = IEEE80211_SKB_CB(skb);
	rates = tx_info->control.rates;

	for (i = 0; i < 4; i++) {
		if (!rates[i].count || rates[i].idx < 0)
			break;

		if (!(rates[i].flags & IEEE80211_TX_RC_MCS))
			return true;
	}

	return false;
}

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.