On Thu, Jun 18, 2026 at 08:00:30AM +0200, Lorenzo Bianconi wrote:

quoted

airoha_tc_htb_alloc_leaf_queue() assigns queue IDs based on the channel
index (opt->qid = AIROHA_NUM_TX_RING + channel), but updates
real_num_tx_queues with a simple increment (num_tx_queues + 1). When QoS
channels are allocated sparsely (e.g., channels 0 and 3 without 1 and
2), the returned qid can exceed real_num_tx_queues, causing out-of-bounds
accesses in the networking stack.
For example, allocating channel 0 then channel 3 results in
real_num_tx_queues = 34 but qid = 35, which is out of range [0, 34).
Fix this by computing real_num_tx_queues based on the highest active
channel index rather than using a simple counter, in both the allocation
and deletion paths.

Fixes: ef1ca9271313b ("net: airoha: Add sched HTB offload support")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
---
 drivers/net/ethernet/airoha/airoha_eth.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c

...

quoted

@@ -2806,7 +2806,10 @@ static int airoha_tc_htb_alloc_leaf_queue(struct net_device *netdev,
 	if (err)
 		goto error;
 
-	err = netif_set_real_num_tx_queues(netdev, num_tx_queues + 1);
+	if (num_tx_queues <= netdev->real_num_tx_queues)
+		goto set_qos_sq_bmap;
+
+	err = netif_set_real_num_tx_queues(netdev, num_tx_queues);
 	if (err) {
 		airoha_qdma_set_tx_rate_limit(netdev, channel, 0,
 					      opt->quantum);

@@ -2815,6 +2818,7 @@ static int airoha_tc_htb_alloc_leaf_queue(struct net_device *netdev,
 		goto error;
 	}
 
+set_qos_sq_bmap:

I would prefer if this could be achieved without a goto.

ack, I will fix it in v2.

Regards,
Lorenzo

quoted

 	set_bit(channel, dev->qos_sq_bmap);
 	opt->qid = AIROHA_NUM_TX_RING + channel;
 

...