Re: [PATCH net-next] net: xilinx: axienet: Add error handling for RX metadata pointer retrieval

[Jakub Kicinski <kuba@kernel.org>]

On Tue, 26 Aug 2025 23:35:49 +0530 Abin Joseph wrote:
> Subject: [PATCH net-next] net: xilinx: axienet: Add error handling for RX metadata pointer retrieval

Sounds like a fix, please repost as [PATCH net], against the
netdev/net tree.

> Add proper error checking for dmaengine_desc_get_metadata_ptr() which
> can return an error pointer and lead to potential crashes or undefined
> behaviour if the pointer retrieval fails.
> 
> Properly handle the error by unmapping DMA buffer, freeing the skb and
> returning early to prevent further processing with invalid data.
> 
> Fixes: 6a91b846af85 ("net: axienet: Introduce dmaengine support")
> Signed-off-by: Abin Joseph <abin.joseph@amd.com>
> ---
>  drivers/net/ethernet/xilinx/xilinx_axienet_main.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> index 0d8a05fe541a..1729fd21d83b 100644
> --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> @@ -1166,8 +1166,17 @@ static void axienet_dma_rx_cb(void *data, const struct dmaengine_result *result)
>  	skb = skbuf_dma->skb;
>  	app_metadata = dmaengine_desc_get_metadata_ptr(skbuf_dma->desc, &meta_len,
>  						       &meta_max_len);
> -	dma_unmap_single(lp->dev, skbuf_dma->dma_address, lp->max_frm_size,
> -			 DMA_FROM_DEVICE);
> +
> +	dma_unmap_single(lp->dev, skbuf_dma->dma_address, lp->max_frm_size, DMA_FROM_DEVICE);

80 char width is still strongly preferred, at least in networking.
So please don't unwrap this line for no apparent reason :\

> +	if (IS_ERR(app_metadata)) {
-- 
pw-bot: cr