From 41d78e9ac0984f0e9577e5312e62400b5a6760c8 Mon Sep 17 00:00:00 2001 From: Lorenzo Bianconi Date: Tue, 27 Oct 2026 14:48:39 +0100 Subject: [PATCH] net: stmmac: copy XDP metadata in AF_XDP zero-copy RX stmmac_construct_skb_zc() reserves headroom for the XDP metadata and records the length reported by the XDP program, but only copies the packet data starting at xdp->data. The bytes in [xdp->data_meta, xdp->data) are never copied into the new skb, so the skb advertises metadata that is not there: after eth_type_trans() anchors mac_header, data_meta points at uninitialized headroom instead of what the program wrote. Copy the metadata together with the packet data starting at xdp->data_meta, leaving skb->data at the start of the frame and the metadata immediately before it, and record its length. This keeps data_meta valid for the stack and TC BPF after eth_type_trans() anchors mac_header. Fixes: bba2556efad6 ("net: stmmac: Enable RX via AF_XDP zero-copy") Signed-off-by: Lorenzo Bianconi Link: https://patch.msgid.link/20261027-stmmac-xdp-fixes-v2-4-10eae8a093a8@oss.qualcomm.com Signed-off-by: Paolo Abeni --- drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index 71858af6fd66..d9fc2464a160 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -5519,7 +5519,8 @@ static struct sk_buff *stmmac_construct_skb_zc(struct stmmac_channel *ch, return NULL; skb_reserve(skb, xdp->data - xdp->data_hard_start); - memcpy(__skb_put(skb, datasize), xdp->data, datasize); + __skb_put(skb, datasize); + memcpy(skb->data - metasize, xdp->data_meta, datasize + metasize); if (metasize) skb_metadata_set(skb, metasize);