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Date: Thu, 24 Sep 2026 08:41:04 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: =?UTF-8?B?VGjDqW8=?= Lebrun <theo.lebrun@bootlin.com>
Cc: <netdev-bot+sashiko@kernel.org>, <conor.dooley@microchip.com>,
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 <maxime.chevallier@bootlin.com>, <stable@vger.kernel.org>
Subject: Re: [PATCH net 1/3] net: macb: never give hardware a NULL RX buffer
Message-ID: <20260924084104.25099f60@kernel.org>
In-Reply-To: <DLNN7LYYGP7L.3OSN8JZNC37PS@bootlin.com>
References: <20260918-macb-close-v1-1-05e32ce98813@bootlin.com>
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On Thu, 24 Sep 2026 17:13:58 +0200 Th=C3=A9o Lebrun wrote:
> > If the AI interprets the rx poll side correctly these seem like a major
> > flaw in setting the USED bit :( =20
>=20
> Yes the AI is correct (unsurprisingly). But two things:

If it's correct then patch needs to be changed.
Please don't write puzzles for me to solve.

>  - before this patch what happened was that HW read the NULL descriptor,
>    so not much better
>  - we can detect in gem_rx() using our ring buffer cursors that tell us
>    what we've managed to allocate, that we gem_rx() doesn't iterate
>    over descriptors that haven't been allocated

Grammatically dubious puzzles at that.