[PATCH v3 net 8/8] net: enetc: fix the off-by-one issue in enetc_map_tx_tso_buffs()

Wei Fang
2025-02-24T11:30:33Z

There is an off-by-one issue for the err_chained_bd path, it will free
one more tx_swbd than expected. But there is no such issue for the
err_map_data path. To fix this off-by-one issue and make the two error
handling consistent, the increment of 'i' and 'count' remain in sync
and enetc_unwind_tx_frame() is called for error handling.

Fixes: fb8629e2cbfc ("net: enetc: add support for software TSO")
Cc: stable@vger.kernel.org
Suggested-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Wei Fang <wei.fang@nxp.com>
---
drivers/net/ethernet/freescale/enetc/enetc.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/net/ethernet/freescale/enetc/enetc.c b/drivers/net/ethernet/freescale/enetc/enetc.c
index 9801c51b6a59..2106861463e4 100644
--- a/drivers/net/ethernet/freescale/enetc/enetc.c
+++ b/drivers/net/ethernet/freescale/enetc/enetc.c
@@ -859,8 +859,13 @@ static int enetc_map_tx_tso_buffs(struct enetc_bdr *tx_ring, struct sk_buff *skb
err = enetc_map_tx_tso_data(tx_ring, skb, tx_swbd, txbd,
tso.data, size,
size == data_len);
- if (err)
+ if (err) {
+ if (i == 0)
+ i = tx_ring->bd_count;
+ i--;
+
goto err_map_data;
+ }

data_len -= size;
count++;
@@ -889,13 +894,7 @@ static int enetc_map_tx_tso_buffs(struct enetc_bdr *tx_ring, struct sk_buff *skb
dev_err(tx_ring->dev, "DMA map error");

err_chained_bd:
- do {
- tx_swbd = &tx_ring->tx_swbd[i];
- enetc_free_tx_frame(tx_ring, tx_swbd);
- if (i == 0)
- i = tx_ring->bd_count;
- i--;
- } while (count--);
+ enetc_unwind_tx_frame(tx_ring, count, i);

return 0;
}
--
2.34.1