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Date: Wed, 19 Aug 2026 16:03:03 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: Tianyu Zuo <cosmosocket@gmail.com>
Cc: Saeed Mahameed <saeedm@nvidia.com>, Tariq Toukan <tariqt@nvidia.com>,
 Mark Bloch <mbloch@nvidia.com>, Leon Romanovsky <leon@kernel.org>, Andrew
 Lunn <andrew+netdev@lunn.ch>, "David S . Miller" <davem@davemloft.net>,
 Eric Dumazet <edumazet@google.com>, Paolo Abeni <pabeni@redhat.com>, Khalid
 Manaa <khalidm@nvidia.com>, Ben Ben-Ishay <benishay@nvidia.com>, Dragos
 Tatulea <dtatulea@nvidia.com>, Simon Horman <horms@kernel.org>,
 netdev@vger.kernel.org, linux-rdma@vger.kernel.org,
 linux-kernel@vger.kernel.org
Subject: Re: [PATCH net v2] net/mlx5e: SHAMPO, Fix IP length overflow on
 large HW GRO sessions
Message-ID: <20260819160303.4be803c5@kernel.org>
In-Reply-To: <20260817181618.2786456-1-cosmosocket@gmail.com>
References: <20260817181618.2786456-1-cosmosocket@gmail.com>
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On Mon, 17 Aug 2026 14:16:18 -0400 Tianyu Zuo wrote:
> mlx5e_hw_gro_skb_has_enough_space() bounds a HW GRO session by the
> payload held in the skb fragments only. The L3/L4 headers that
> header-data split placed in the linear area are not accounted for, and
> the limit is inclusive of GRO_LEGACY_MAX_SIZE.

This regresses both ipv4-large-rem and ipv6-large-rem on CX7

# # Exception|   STDERR: Expected {64896 600 600 }, Total 3 packets
# # Exception|           Received {60840 [!=64896]4656 [!=600]600 }, Total 3 packets.

we could have fit another MSS into the aggregate, easily.
-- 
pw-bot: cr