ath10k: guard against CE corruption from firmware

In case firmware crashes it may report CE
completions for entries that were never
submitted/filled with meaningful data. This in
turn led to NULL dereferences.
Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/ath10k/htc.c

@@ -191,6 +191,11 @@ static int ath10k_htc_tx_completion_handler(struct ath10k *ar,
 	struct ath10k_htc *htc = &ar->htc;
 	struct ath10k_htc_ep *ep = &htc->endpoint[eid];
 
+	if (!skb) {
+		ath10k_warn("invalid sk_buff completion - NULL pointer. firmware crashed?\n");
+		return 0;
+	}
+
 	ath10k_htc_notify_tx_completion(ep, skb);
 	/* the skb now belongs to the completion handler */
 

drivers/net/wireless/ath/ath10k/pci.c

@@ -1270,6 +1270,13 @@ static void ath10k_pci_tx_pipe_cleanup(struct ath10k_pci_pipe *pipe_info)
 		 * Indicate the completion to higer layer to free
 		 * the buffer
 		 */
+
+		if (!netbuf) {
+			ath10k_warn("invalid sk_buff on CE %d - NULL pointer. firmware crashed?\n",
+				    ce_hdl->id);
+			continue;
+		}
+
 		ATH10K_SKB_CB(netbuf)->is_aborted = true;
 		ar_pci->msg_callbacks_current.tx_completion(ar,
 							    netbuf,