From: Andrew Lunn <andrew@lunn.ch>
To: Aldo Ariel <qwe.aldo@gmail.com>
Cc: wei.fang@nxp.com, frank.li@nxp.com, shenwei.wang@nxp.com,
imx@lists.linux.dev, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, stable@vger.kernel.org,
sashiko-bot@kernel.org
Subject: Re: Re: [PATCH net v2] net: fec: reject oversized fragments before bounce-buffer memcpy
Date: Wed, 7 Oct 2026 14:27:24 +0200 [thread overview]
Message-ID: <36643418-851b-4cbf-ab73-8e3fa09f8715@lunn.ch> (raw)
In-Reply-To: <CAP48HfuR9_d2KZ7ygG4fMq5ekSb2zaaiEzo_fq_mOWODN5Os6A@mail.gmail.com>
On Wed, Oct 07, 2026 at 05:17:20AM -0700, Aldo Ariel wrote:
> Hi Andrew, Wei, Shenwei,
>
> Thank you for the review. Shenwei confirmed that bounce buffers are
> only available on i.MX28 and cannot coexist with jumbo frames. That
> means the overflow path I described (jumbo fragments exceeding
> FEC_ENET_TX_FRSIZE) is not reachable in practice: on i.MX28 the
> max_mtu stays below the bounce buffer capacity.
>
> Given that, should I respin as a defense-in-depth guard (with the
> goto label fixed per Wei's note), or would you prefer I withdraw the
> patch?
I suggest adding a comment somewhere to explain that jumbo frames and
bounce buffers are mutually exclusive by hardware design.
We don't use defensive code, because that suggests we don't actually
understand the code!
Andrew
next prev parent reply other threads:[~2026-10-07 12:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-23 20:37 [PATCH net v2] net: fec: reject oversized fragments before bounce-buffer memcpy Aldo Ariel Panzardo
2026-09-23 21:00 ` Andrew Lunn
[not found] ` <CAP48Hfto4qc285B3Jw7ZRuC-wGf57JOBPZOdrrAt-aDfGcas8Q@mail.gmail.com>
2026-09-24 12:40 ` Andrew Lunn
2026-09-24 15:24 ` Shenwei Wang
[not found] ` <CAP48HfuR9_d2KZ7ygG4fMq5ekSb2zaaiEzo_fq_mOWODN5Os6A@mail.gmail.com>
2026-10-07 12:27 ` Andrew Lunn [this message]
2026-09-24 2:15 ` Wei Fang
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