The transmit loop in airoha_dev_xmit() reads fragment address and length during its final iteration, when the loop index equals skb_shinfo(skb)->nr_frags, at which point the fragment data is uninitialized. While these values are never consumed, the read itself is unsafe and may trigger a page fault. Fix this by avoiding the fragment read on the last iteration. Additionally, move the skb pointer from the first to the last used packet descriptor, so that airoha_qdma_tx_napi_poll() defers freeing the skb until the final descriptor is processed. Fixes: 23020f0493270 ("net: airoha: Introduce ethernet support for EN7581 SoC") Signed-off-by: Lorenzo Bianconi --- drivers/net/ethernet/airoha/airoha_eth.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/airoha/airoha_eth.c b/drivers/net/ethernet/airoha/airoha_eth.c index 2bb0a3ff9810..d3a841908c82 100644 --- a/drivers/net/ethernet/airoha/airoha_eth.c +++ b/drivers/net/ethernet/airoha/airoha_eth.c @@ -1997,8 +1997,8 @@ static netdev_tx_t airoha_dev_xmit(struct sk_buff *skb, struct netdev_queue *txq; struct airoha_queue *q; LIST_HEAD(tx_list); + int i = 0, qid; void *data; - int i, qid; u16 index; u8 fport; @@ -2057,7 +2057,7 @@ static netdev_tx_t airoha_dev_xmit(struct sk_buff *skb, list); index = e - q->entry; - for (i = 0; i < nr_frags; i++) { + while (true) { struct airoha_qdma_desc *desc = &q->desc[index]; skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; dma_addr_t addr; @@ -2069,7 +2069,7 @@ static netdev_tx_t airoha_dev_xmit(struct sk_buff *skb, goto error_unmap; list_move_tail(&e->list, &tx_list); - e->skb = i ? NULL : skb; + e->skb = i == nr_frags - 1 ? skb : NULL; e->dma_addr = addr; e->dma_len = len; @@ -2088,6 +2088,9 @@ static netdev_tx_t airoha_dev_xmit(struct sk_buff *skb, WRITE_ONCE(desc->msg1, cpu_to_le32(msg1)); WRITE_ONCE(desc->msg2, cpu_to_le32(0xffff)); + if (++i == nr_frags) + break; + data = skb_frag_address(frag); len = skb_frag_size(frag); } --- base-commit: e728258debd553c95d2e70f9cd97c9fde27c7130 change-id: 20260423-airoha-xmit-fix-read-frag-dc6aa001ca4b Best regards, -- Lorenzo Bianconi