From: Jakub Kicinski <kuba@kernel.org>
To: Mohsin Bashir <mohsin.bashr@gmail.com>
Cc: Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
netdev@vger.kernel.org, alexanderduyck@fb.com,
andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com,
pabeni@redhat.com, horms@kernel.org, vadim.fedorenko@linux.dev,
jdamato@fastly.com, sdf@fomichev.me,
aleksander.lobakin@intel.com, ast@kernel.org,
daniel@iogearbox.net, hawk@kernel.org, john.fastabend@gmail.com
Subject: Re: [PATCH net-next 5/9] eth: fbnic: Add XDP pass, drop, abort support
Date: Thu, 24 Jul 2025 09:51:08 -0700 [thread overview]
Message-ID: <20250724095108.186fe3a1@kernel.org> (raw)
In-Reply-To: <3b1f10aa-49a2-465b-8b11-bf5e92a6bf8f@gmail.com>
On Thu, 24 Jul 2025 08:47:20 -0700 Mohsin Bashir wrote:
> >> + if (xdp_buff_has_frags(&pkt->buff) && !xdp_prog->aux->xdp_has_frags)
> >> + return ERR_PTR(-FBNIC_XDP_LEN_ERR);
> >
> > when can this happen and couldn't you catch this within ndo_bpf? i suppose
> > it's related to hds setup.
>
> It is important to avoid passing a packet with frags to a single-buff
> XDP program. The implication being that a single-buff XDP program would
> fail to access packet linearly. For example, we can send a jumbo UDP
> packet to the SUT with a single-buffer XDP program attached and in the
> XDP program, attempt to access payload linearly.
>
> I believe handling this case within ndo_bpf may not be possible.
Herm, we are handling it in ndo_bpf..
This check is just a safety in case somehow we get a packet larger
than MTU, and therefore crossing the "safe" HDS threshold.
next prev parent reply other threads:[~2025-07-24 16:51 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-23 14:59 [PATCH net-next 0/9] eth: fbnic Add XDP support for fbnic Mohsin Bashir
2025-07-23 14:59 ` [PATCH net-next 1/9] eth: fbnic: Add support for HDS configuration Mohsin Bashir
2025-07-23 14:59 ` [PATCH net-next 2/9] eth: fbnic: Update Headroom Mohsin Bashir
2025-07-23 14:59 ` [PATCH net-next 3/9] eth: fbnic: Use shinfo to track frags state on Rx Mohsin Bashir
2025-07-23 14:59 ` [PATCH net-next 4/9] eth: fbnic: Prefetch packet headers " Mohsin Bashir
2025-07-23 14:59 ` [PATCH net-next 5/9] eth: fbnic: Add XDP pass, drop, abort support Mohsin Bashir
2025-07-23 17:35 ` Maciej Fijalkowski
2025-07-24 15:47 ` Mohsin Bashir
2025-07-24 16:51 ` Jakub Kicinski [this message]
2025-07-24 21:14 ` Alexander H Duyck
2025-07-25 9:56 ` Maciej Fijalkowski
2025-07-25 15:10 ` Alexander Duyck
2025-08-07 21:24 ` Mohsin Bashir
2025-07-23 14:59 ` [PATCH net-next 6/9] eth: fbnic: Add support for XDP queues Mohsin Bashir
2025-07-23 23:54 ` Jakub Kicinski
2025-07-23 14:59 ` [PATCH net-next 7/9] eth: fbnic: Add support for XDP_TX action Mohsin Bashir
2025-07-23 14:59 ` [PATCH net-next 8/9] eth: fbnic: Collect packet statistics for XDP Mohsin Bashir
2025-07-24 10:18 ` Simon Horman
2025-07-24 15:48 ` Mohsin Bashir
2025-07-23 14:59 ` [PATCH net-next 9/9] eth: fbnic: Report XDP stats via ethtool Mohsin Bashir
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