net: ieee802154: at86rf230: Stop leaking skb's

[ Upstream commit e5ce576 ]

Upon error the ieee802154_xmit_complete() helper is not called. Only
ieee802154_wake_queue() is called manually. In the Tx case we then leak
the skb structure.

Free the skb structure upon error before returning when appropriate.

As the 'is_tx = 0' cannot be moved in the complete handler because of a
possible race between the delay in switching to STATE_RX_AACK_ON and a
new interrupt, we introduce an intermediate 'was_tx' boolean just for
this purpose.

There is no Fixes tag applying here, many changes have been made on this
area and the issue kind of always existed.

Suggested-by: Alexander Aring <alex.aring@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Alexander Aring <aahringo@redhat.com>
Link: https://lore.kernel.org/r/20220125121426.848337-4-miquel.raynal@bootlin.com
Signed-off-by: Stefan Schmidt <stefan@datenfreihafen.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/net/ieee802154/at86rf230.c

@@ -100,6 +100,7 @@ struct at86rf230_local {
 	unsigned long cal_timeout;
 	bool is_tx;
 	bool is_tx_from_off;
+	bool was_tx;
 	u8 tx_retry;
 	struct sk_buff *tx_skb;
 	struct at86rf230_state_change tx;
@@ -343,7 +344,11 @@ at86rf230_async_error_recover_complete(void *context)
 	if (ctx->free)
 		kfree(ctx);
 
-	ieee802154_wake_queue(lp->hw);
+	if (lp->was_tx) {
+		lp->was_tx = 0;
+		dev_kfree_skb_any(lp->tx_skb);
+		ieee802154_wake_queue(lp->hw);
+	}
 }
 
 static void
@@ -352,7 +357,11 @@ at86rf230_async_error_recover(void *context)
 	struct at86rf230_state_change *ctx = context;
 	struct at86rf230_local *lp = ctx->lp;
 
-	lp->is_tx = 0;
+	if (lp->is_tx) {
+		lp->was_tx = 1;
+		lp->is_tx = 0;
+	}
+
 	at86rf230_async_state_change(lp, ctx, STATE_RX_AACK_ON,
 				     at86rf230_async_error_recover_complete);
 }