Messages in this thread | | | Date | Tue, 23 May 2023 20:42:57 -0700 | From | Jakub Kicinski <> | Subject | Re: [PATCH net] net: mellanox: mlxbf_gige: Fix skb_panic splat under memory pressure |
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On Mon, 22 May 2023 21:07:13 +0200 Thomas Bogendoerfer wrote: > Do skp_put() after a new skb has been successfully allocated otherwise > the reused skb leads to skp_panics or incorrect packet sizes.
s/skp/skb/
Please add a Fixes tag pointing at the patch which introduced the problem (could be the first commit adding this driver).
> Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de> > --- > .../ethernet/mellanox/mlxbf_gige/mlxbf_gige_rx.c | 13 +++++++------ > 1 file changed, 7 insertions(+), 6 deletions(-) > > diff --git a/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_rx.c b/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_rx.c > index afa3b92a6905..2c132849a76d 100644 > --- a/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_rx.c > +++ b/drivers/net/ethernet/mellanox/mlxbf_gige/mlxbf_gige_rx.c > @@ -245,18 +245,19 @@ static bool mlxbf_gige_rx_packet(struct mlxbf_gige *priv, int *rx_pkts) > > skb = priv->rx_skb[rx_pi_rem]; > > - skb_put(skb, datalen); > - > - skb->ip_summed = CHECKSUM_NONE; /* device did not checksum packet */ > - > - skb->protocol = eth_type_trans(skb, netdev); > - > /* Alloc another RX SKB for this same index */ > rx_skb = mlxbf_gige_alloc_skb(priv, MLXBF_GIGE_DEFAULT_BUF_SZ, > &rx_buf_dma, DMA_FROM_DEVICE); > if (!rx_skb) > return false; > priv->rx_skb[rx_pi_rem] = rx_skb; > + > + skb_put(skb, datalen); > + > + skb->ip_summed = CHECKSUM_NONE; /* device did not checksum packet */ > + > + skb->protocol = eth_type_trans(skb, netdev); > > dma_unmap_single(priv->dev, *rx_wqe_addr, > MLXBF_GIGE_DEFAULT_BUF_SZ, DMA_FROM_DEVICE);
You should move the code here, after the dma_unmap(). eth_type_trans() will access the payload and until dma_unmap the data should not be accessed by the CPU.
> *rx_wqe_addr = rx_buf_dma;
-- pw-bot: cr
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