wifi: ath11k: fix htt pktlog locking

commit 3f77c7d upstream.

The ath11k active pdevs are protected by RCU but the htt pktlog handling
code calling ath11k_mac_get_ar_by_pdev_id() was not marked as a
read-side critical section.

Mark the code in question as an RCU read-side critical section to avoid
any potential use-after-free issues.

Compile tested only.

Fixes: d5c6515 ("ath11k: driver for Qualcomm IEEE 802.11ax devices")
Cc: stable@vger.kernel.org      # 5.6
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20231019112521.2071-1-johan+linaro@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/net/wireless/ath/ath11k/dp_rx.c

@@ -1621,14 +1621,20 @@ static void ath11k_htt_pktlog(struct ath11k_base *ab, struct sk_buff *skb)
 	u8 pdev_id;
 
 	pdev_id = FIELD_GET(HTT_T2H_PPDU_STATS_INFO_PDEV_ID, data->hdr);
+
+	rcu_read_lock();
+
 	ar = ath11k_mac_get_ar_by_pdev_id(ab, pdev_id);
 	if (!ar) {
 		ath11k_warn(ab, "invalid pdev id %d on htt pktlog\n", pdev_id);
-		return;
+		goto out;
 	}
 
 	trace_ath11k_htt_pktlog(ar, data->payload, hdr->size,
 				ar->ab->pktlog_defs_checksum);
+
+out:
+	rcu_read_unlock();
 }
 
 static void ath11k_htt_backpressure_event_handler(struct ath11k_base *ab,