[PATCH net v1 2/3] hinic3: fix use-after-free on DMA mapping failure

[xuanqiang.luo@linux.dev]

From: Xuanqiang Luo <luoxuanqiang@kylinos.cn>

If hinic3_tx_map_skb() fails in hinic3_send_one_skb(), the skb is freed,
but tx_info->skb was set before the mapping attempt and is not cleared. The
SQ producer index is rolled back, so later transmissions normally overwrite
the entry.

If the interface is brought down first, hinic3_free_txqs_res() calls
free_all_tx_skbs(). It scans the entire tx_info array and finds the stale
pointer. hinic3_tx_unmap_skb() then dereferences the freed skb in
skb_shinfo(), before it is freed again.

Set tx_info->skb and its WQEBB count only after DMA mapping succeeds,
preventing the stale pointer from reaching free_all_tx_skbs().

Fixes: 17fcb3dc12bb ("hinic3: module initialization and tx/rx logic")
Cc: stable@vger.kernel.org
Assisted-by: Opencode:deepseek-v4-pro[1m]
Signed-off-by: Xuanqiang Luo <luoxuanqiang@kylinos.cn>
---
 drivers/net/ethernet/huawei/hinic3/hinic3_tx.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/huawei/hinic3/hinic3_tx.c b/drivers/net/ethernet/huawei/hinic3/hinic3_tx.c
index 9306bf0020caf..5739ecb08d0d3 100644
--- a/drivers/net/ethernet/huawei/hinic3/hinic3_tx.c
+++ b/drivers/net/ethernet/huawei/hinic3/hinic3_tx.c
@@ -578,8 +578,6 @@ static netdev_tx_t hinic3_send_one_skb(struct sk_buff *skb,
 		*wqe_combo.task = task;
 
 	tx_info = &txq->tx_info[pi];
-	tx_info->skb = skb;
-	tx_info->wqebb_cnt = wqebb_cnt;
 
 	err = hinic3_tx_map_skb(netdev, skb, txq, tx_info, &wqe_combo);
 	if (err) {
@@ -589,6 +587,9 @@ static netdev_tx_t hinic3_send_one_skb(struct sk_buff *skb,
 		goto err_drop_pkt;
 	}
 
+	tx_info->skb = skb;
+	tx_info->wqebb_cnt = wqebb_cnt;
+
 	netif_subqueue_sent(netdev, txq->sq->q_id, skb->len);
 	netif_subqueue_maybe_stop(netdev, txq->sq->q_id,
 				  hinic3_wq_free_wqebbs(&txq->sq->wq),
-- 
2.43.0