Re: [PATCH net v3] ip6_gre: use skb_vlan_inet_prepare() instead of pskb_inet_may_pull()

On Mon, Jan 19, 2026 at 6:06 PM Jakub Kicinski [off-list ref] wrote:

On Mon, 19 Jan 2026 12:24:57 +0100 Florian Westphal wrote:

quoted

From: Eric Dumazet <redacted>

I added skb_vlan_inet_prepare() helper in the cited commit, hinting
that we would need to use it more broadly.

I _think_ this makes GRE forwarding tests a bit unhappy:

https://netdev.bots.linux.dev/contest.html?branch=net-next-2026-01-19--12-00&executor=vmksft-forwarding&pw-n=0&pass=0
--

I was unsure about ip6erspan_tunnel_xmit() change, I think I started
full tests days ago but probably was distracted.

I had :

diff --git a/net/ipv6/ip6_gre.c b/net/ipv6/ip6_gre.c
index d19d86ed43766bbc8ec052113be02ab231a5272c..9e214c355e6ce15fa828866ae20fa8fe321b4bf7

100644

--- a/net/ipv6/ip6_gre.c
+++ b/net/ipv6/ip6_gre.c

@@ -881,7 +881,7 @@ static netdev_tx_t ip6gre_tunnel_xmit(struct sk_buff *skb,
        __be16 payload_protocol;
        int ret;

-       if (!pskb_inet_may_pull(skb))
+       if (skb_vlan_inet_prepare(skb, true))
                goto tx_err;

        if (!ip6_tnl_xmit_ctl(t, &t->parms.laddr, &t->parms.raddr))

@@ -929,7 +929,7 @@ static netdev_tx_t ip6erspan_tunnel_xmit(struct

sk_buff *skb,
        __u32 mtu;
        int nhoff;

-       if (!pskb_inet_may_pull(skb))
+       if (skb_vlan_inet_prepare(skb, false))
                goto tx_err;

        if (!ip6_tnl_xmit_ctl(t, &t->parms.laddr, &t->parms.raddr))