netdev - [PATCH bpf-next v2 04/15] bpf: Make bpf_skb_vlan

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Message-Id: <20251019-skb-meta-rx-path-v2-4-f9a58f3eb6d6@cloudflare.com>
Date: Sun, 19 Oct 2025 14:45:28 +0200
From: Jakub Sitnicki <jakub@...udflare.com>
To: bpf@...r.kernel.org
Cc: "David S. Miller" <davem@...emloft.net>, 
 Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, 
 Paolo Abeni <pabeni@...hat.com>, Simon Horman <horms@...nel.org>, 
 Martin KaFai Lau <martin.lau@...ux.dev>, 
 Daniel Borkmann <daniel@...earbox.net>, 
 John Fastabend <john.fastabend@...il.com>, 
 Stanislav Fomichev <sdf@...ichev.me>, Alexei Starovoitov <ast@...nel.org>, 
 Andrii Nakryiko <andrii@...nel.org>, Eduard Zingerman <eddyz87@...il.com>, 
 Song Liu <song@...nel.org>, Yonghong Song <yonghong.song@...ux.dev>, 
 KP Singh <kpsingh@...nel.org>, Hao Luo <haoluo@...gle.com>, 
 Jiri Olsa <jolsa@...nel.org>, Arthur Fabre <arthur@...hurfabre.com>, 
 netdev@...r.kernel.org, kernel-team@...udflare.com
Subject: [PATCH bpf-next v2 04/15] bpf: Make bpf_skb_vlan_pop helper
 metadata-safe

Use the metadata-aware helper to move packet bytes after skb_pull(),
ensuring metadata remains valid after calling the BPF helper.

Signed-off-by: Jakub Sitnicki <jakub@...udflare.com>
---
 include/linux/if_vlan.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h
index afa5cc61a0fa..4ecc2509b0d4 100644
--- a/include/linux/if_vlan.h
+++ b/include/linux/if_vlan.h
@@ -738,9 +738,9 @@ static inline void vlan_remove_tag(struct sk_buff *skb, u16 *vlan_tci)

 	*vlan_tci = ntohs(vhdr->h_vlan_TCI);

-	memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
 	vlan_set_encap_proto(skb, vhdr);
 	__skb_pull(skb, VLAN_HLEN);
+	skb_postpull_data_move(skb, VLAN_HLEN, 2 * ETH_ALEN);
 }

 /**

-- 
2.43.0