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Message-ID: <566fb566-4806-41bc-ae6f-7f4ef5762a7b@nvidia.com>
Date: Thu, 5 Dec 2024 13:55:24 +0000
From: Jon Hunter <jonathanh@...dia.com>
To: Furong Xu <0x1207@...il.com>, netdev@...r.kernel.org,
linux-stm32@...md-mailman.stormreply.com,
linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc: andrew+netdev@...n.ch, Alexandre Torgue <alexandre.torgue@...s.st.com>,
Jose Abreu <joabreu@...opsys.com>, "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
Paolo Abeni <pabeni@...hat.com>, Maxime Coquelin
<mcoquelin.stm32@...il.com>, xfr@...look.com,
Thierry Reding <thierry.reding@...il.com>,
Russell King <linux@...linux.org.uk>,
"linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>
Subject: Re: [PATCH net v1] net: stmmac: TSO: Fix unaligned DMA unmap for
non-paged SKB data
On 05/12/2024 09:18, Furong Xu wrote:
> Commit 66600fac7a98 ("net: stmmac: TSO: Fix unbalanced DMA map/unmap for
> non-paged SKB data") assigns a wrong DMA buffer address that is added an
> offset of proto_hdr_len to tx_q->tx_skbuff_dma[entry].buf on a certain
> platform that the DMA AXI address width is configured to 40-bit/48-bit,
In our case it is 40/40 ...
dwc-eth-dwmac 2490000.ethernet: Using 40/40 bits DMA host/device width
> stmmac_tx_clean() will try to unmap this illegal DMA buffer address
> and many crashes are reported: [1] [2].
>
> This patch guarantees that DMA address is passed to stmmac_tx_clean()
> unmodified and without offset.
>
> [1] https://lore.kernel.org/all/d8112193-0386-4e14-b516-37c2d838171a@nvidia.com/
> [2] https://lore.kernel.org/all/klkzp5yn5kq5efgtrow6wbvnc46bcqfxs65nz3qy77ujr5turc@bwwhelz2l4dw/
>
> Reported-by: Jon Hunter <jonathanh@...dia.com>
> Reported-by: Thierry Reding <thierry.reding@...il.com>
> Suggested-by: Russell King (Oracle) <linux@...linux.org.uk>
> Fixes: 66600fac7a98 ("net: stmmac: TSO: Fix unbalanced DMA map/unmap for non-paged SKB data")
> Signed-off-by: Furong Xu <0x1207@...il.com>
> ---
> drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> index 9b262cdad60b..7227f8428b5e 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
> @@ -4192,8 +4192,8 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb, struct net_device *dev)
> struct stmmac_txq_stats *txq_stats;
> struct stmmac_tx_queue *tx_q;
> u32 pay_len, mss, queue;
> + dma_addr_t tso_hdr, des;
> u8 proto_hdr_len, hdr;
> - dma_addr_t des;
> bool set_ic;
> int i;
>
> @@ -4279,6 +4279,7 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb, struct net_device *dev)
> DMA_TO_DEVICE);
> if (dma_mapping_error(priv->device, des))
> goto dma_map_err;
> + tso_hdr = des;
>
> if (priv->dma_cap.addr64 <= 32) {
> first->des0 = cpu_to_le32(des);
> @@ -4310,7 +4311,7 @@ static netdev_tx_t stmmac_tso_xmit(struct sk_buff *skb, struct net_device *dev)
> * this DMA buffer right after the DMA engine completely finishes the
> * full buffer transmission.
> */
> - tx_q->tx_skbuff_dma[tx_q->cur_tx].buf = des;
> + tx_q->tx_skbuff_dma[tx_q->cur_tx].buf = tso_hdr;
> tx_q->tx_skbuff_dma[tx_q->cur_tx].len = skb_headlen(skb);
> tx_q->tx_skbuff_dma[tx_q->cur_tx].map_as_page = false;
> tx_q->tx_skbuff_dma[tx_q->cur_tx].buf_type = STMMAC_TXBUF_T_SKB;
Otherwise ...
Tested-by: Jon Hunter <jonathanh@...dia.com>
Jon
--
nvpublic
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