linux-kernel - RE: [PATCH net] net: stmmac: fix the crash issue for zero copy XDP

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Date: Wed, 17 Dec 2025 12:49:19 +0000
From: Wei Fang <wei.fang@....com>
To: Hariprasad Kelam <hkelam@...vell.com>
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Subject: RE: [PATCH net] net: stmmac: fix the crash issue for zero copy XDP_TX
 action

> > -	res = stmmac_xdp_xmit_xdpf(priv, queue, xdpf, false);
> > -	if (res == STMMAC_XDP_TX)
> > +	/* For zero copy XDP_TX action, dma_map is true */
> > +	res = stmmac_xdp_xmit_xdpf(priv, queue, xdpf, zc);
> 	Seems stmmac_xdp_xmit_xdpf is using dma_map_single if we pass zc is
> true.
>         Ideally in case of zc, driver can use page_pool_get_dma_addr, may be
> you
>         need pass zc param as false. Please check
> 

No, the memory type of xdpf->data is MEM_TYPE_PAGE_ORDER0 rather
than MEM_TYPE_PAGE_POOL, so we should use dma_map_single().
Otherwise, it will lead to invalid mappings and cause the crash.