[PATCH net] geneve: fix length used in GRO hint UDP checksum adjustment

[PATCH net] geneve: fix length used in GRO hint UDP checksum adjustment

[Antoine Tenart]

In geneve_post_decap_hint the length used for adjusting the UDP checksum
should be 'skb->len - gro_hint->nested_tp_offset' (UDP length) instead
of 'skb->len - gro_hint->nested_nh_offset' (IP length).

Fixes: fd0dd796576e ("geneve: use GRO hint option in the RX path")
Cc: Paolo Abeni <pabeni@redhat.com>
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260521131436.748832-1-jhs%40mojatatu.com
Signed-off-by: Antoine Tenart <atenart@kernel.org>
---
 drivers/net/geneve.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index c6563367d382..715180c3a1b3 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -632,7 +632,7 @@ static int geneve_post_decap_hint(const struct sock *sk, struct sk_buff *skb,
 	uh = udp_hdr(skb);
 	uh->len = htons(skb->len - gro_hint->nested_tp_offset);
 	if (uh->check) {
-		len = skb->len - gro_hint->nested_nh_offset;
+		len = skb->len - gro_hint->nested_tp_offset;
 		skb_shinfo(skb)->gso_type |= SKB_GSO_UDP_TUNNEL_CSUM;
 		if (gro_hint->nested_is_v6)
 			uh->check = ~udp_v6_check(len, &ipv6h->saddr,
-- 
2.54.0

Re: [PATCH net] geneve: fix length used in GRO hint UDP checksum adjustment

[Simon Horman]

On Fri, May 29, 2026 at 04:47:00PM +0200, Antoine Tenart wrote:
> In geneve_post_decap_hint the length used for adjusting the UDP checksum
> should be 'skb->len - gro_hint->nested_tp_offset' (UDP length) instead
> of 'skb->len - gro_hint->nested_nh_offset' (IP length).
> 
> Fixes: fd0dd796576e ("geneve: use GRO hint option in the RX path")
> Cc: Paolo Abeni <pabeni@redhat.com>
> Reported-by: Sashiko <sashiko-bot@kernel.org>
> Closes: https://sashiko.dev/#/patchset/20260521131436.748832-1-jhs%40mojatatu.com
> Signed-off-by: Antoine Tenart <atenart@kernel.org>

Reviewed-by: Simon Horman <horms@kernel.org>

FTR, an AI-generated review of this patch is available on sashiko.dev.
I do not believe that needs to be addressed in the context of this patch.