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Date: Mon, 9 Feb 2026 15:41:38 +0000
From: Simon Horman <horms@kernel.org>
To: Ethan Nelson-Moore <enelsonmoore@gmail.com>
Cc: netdev@vger.kernel.org, stable@vger.kernel.org,
	Michael Grzeschik <m.grzeschik@pengutronix.de>,
	Andrew Lunn <andrew+netdev@lunn.ch>,
	"David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
	Zheyu Ma <zheyuma97@gmail.com>
Subject: Re: [PATCH net-next] net: arcnet: com20020-pci: fix support for
 2.5Mbit cards
Message-ID: <aYoAMrEVDNydXQdq@horms.kernel.org>
References: <20260205065113.33547-1-enelsonmoore@gmail.com>
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In-Reply-To: <20260205065113.33547-1-enelsonmoore@gmail.com>

On Wed, Feb 04, 2026 at 10:51:12PM -0800, Ethan Nelson-Moore wrote:
> Commit 8c14f9c70327 ("ARCNET: add com20020 PCI IDs with metadata")
> converted the com20020-pci driver to use a card info structure instead
> of a single flag mask in driver_data. However, it failed to take into
> account that in the original code, driver_data of 0 indicates a card
> with no special flags, not a card that should not have any card info
> structure. This introduced a null pointer dereference when cards with
> no flags were probed.
> 
> Commit bd6f1fd5d33d ("net: arcnet: com20020: Fix null-ptr-deref in
> com20020pci_probe()") then papered over this issue by rejecting cards
> with no driver_data instead of resolving the problem at its source.
> 
> Revert the incorrect fix and fix the original issue by introducing a
> new card info structure for 2.5Mbit cards that does not set any flags.
> 
> Fixes: 8c14f9c70327 ("ARCNET: add com20020 PCI IDs with metadata")
> Fixes: bd6f1fd5d33d ("net: arcnet: com20020: Fix null-ptr-deref in com20020pci_probe()")
> Cc: stable@vger.kernel.org
> Signed-off-by: Ethan Nelson-Moore <enelsonmoore@gmail.com>

I do wonder if this should be targeted at net rather than net-next.
But at any rate, looking over the cited commits, the change looks good to
me.

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

...