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Date: Wed, 8 Apr 2026 18:02:06 +0100
From: Simon Horman <horms@kernel.org>
To: David Carlier <devnexen@gmail.com>
Cc: Veerasenareddy Burru <vburru@marvell.com>,
	Sathesh Edara <sedara@marvell.com>,
	Shinas Rasheed <srasheed@marvell.com>,
	Satananda Burla <sburla@marvell.com>,
	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>,
	netdev@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH] octeon_ep_vf: add NULL check for napi_build_skb()
Message-ID: <20260408170206.GI469338@kernel.org>
References: <20260403200732.497307-1-devnexen@gmail.com>
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In-Reply-To: <20260403200732.497307-1-devnexen@gmail.com>

On Fri, Apr 03, 2026 at 09:07:32PM +0100, David Carlier wrote:
> napi_build_skb() can return NULL on allocation failure. In
> __octep_vf_oq_process_rx(), the result is used directly without a NULL
> check in both the single-buffer and multi-fragment paths, leading to a
> NULL pointer dereference.
> 
> Add NULL checks after both napi_build_skb() calls, properly advancing
> descriptors and consuming remaining fragments on failure.
> 
> Fixes: 1cd3b407977c ("octeon_ep_vf: add Tx/Rx processing and interrupt support")
> Cc: stable@vger.kernel.org
> Signed-off-by: David Carlier <devnexen@gmail.com>

Hi David,

I appreciate that this is on the fast path, and thus I expect it
is performance critical. But this patch largely duplicates code
already present in the same function. Would it be possible
refactor things a bit - e.g. using helpers - to make the change
a bit cleaner while not hurting performance?

If so, I'd suggest splitting patch(es) that refactor the code
from the patch that fixes the bug.

...