Re: [PATCH] net: ethernet: mtk-star-emac: fix wrong unmap in RX handling
From: Bartosz Golaszewski <hidden>
Date: 2021-03-02 09:21:39
Also in:
linux-arm-kernel, linux-mediatek, lkml
On Tue, Mar 2, 2021 at 4:33 AM Biao Huang [off-list ref] wrote:
quoted hunk ↗ jump to hunk
mtk_star_dma_unmap_rx() should unmap the dma_addr of old skb rather than that of new skb. Assign new_dma_addr to desc_data.dma_addr after all handling of old skb ends to avoid unexpected receive side error. Fixes: f96e9641e92b ("net: ethernet: mtk-star-emac: fix error path in RX handling") Signed-off-by: Biao Huang <redacted> --- drivers/net/ethernet/mediatek/mtk_star_emac.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)diff --git a/drivers/net/ethernet/mediatek/mtk_star_emac.c b/drivers/net/ethernet/mediatek/mtk_star_emac.c index a8641a407c06..96d2891f1675 100644 --- a/drivers/net/ethernet/mediatek/mtk_star_emac.c +++ b/drivers/net/ethernet/mediatek/mtk_star_emac.c@@ -1225,8 +1225,6 @@ static int mtk_star_receive_packet(struct mtk_star_priv *priv) goto push_new_skb; } - desc_data.dma_addr = new_dma_addr; - /* We can't fail anymore at this point: it's safe to unmap the skb. */ mtk_star_dma_unmap_rx(priv, &desc_data);@@ -1236,6 +1234,9 @@ static int mtk_star_receive_packet(struct mtk_star_priv *priv) desc_data.skb->dev = ndev; netif_receive_skb(desc_data.skb); + /* update dma_addr for new skb */ + desc_data.dma_addr = new_dma_addr; + push_new_skb: desc_data.len = skb_tailroom(new_skb); desc_data.skb = new_skb; --2.18.0
Thanks for spotting that. Maybe also update the commit so that it says: "it's safe to unmap the old skb"? Would make the thing clearer IMO. In any case: Acked-by: Bartosz Golaszewski <redacted> Bartosz