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Date: Tue, 19 Dec 2023 10:52:59 +0000
From: Simon Horman <horms@kernel.org>
To: Lorenzo Bianconi <lorenzo@kernel.org>
Cc: netdev@vger.kernel.org, lorenzo.bianconi@redhat.com, nbd@nbd.name,
	john@phrozen.org, sean.wang@mediatek.com, Mark-MC.Lee@mediatek.com,
	davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
	pabeni@redhat.com
Subject: Re: [PATCH net] net: ethernet: mtk_wed: fix possible NULL pointer
 dereference in mtk_wed_wo_queue_tx_clean()
Message-ID: <20231219105259.GF811967@kernel.org>
References: <3c1262464d215faa8acebfc08869798c81c96f4a.1702827359.git.lorenzo@kernel.org>
 <20231218175548.GI6288@kernel.org>
 <ZYC2m3mMhfOpDN2j@lore-desk>
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In-Reply-To: <ZYC2m3mMhfOpDN2j@lore-desk>

On Mon, Dec 18, 2023 at 10:16:11PM +0100, Lorenzo Bianconi wrote:
> > On Sun, Dec 17, 2023 at 04:37:40PM +0100, Lorenzo Bianconi wrote:
> > > In order to avoid a NULL pointer dereference, check entry->buf pointer before running
> > > skb_free_frag in mtk_wed_wo_queue_tx_clean routine.
> > > 
> > > Fixes: 799684448e3e ("net: ethernet: mtk_wed: introduce wed wo support")
> > > Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
> > 
> > Hi Lorenzo,
> 
> Hi Simon,
> 
> > 
> > can I clarify that this can actually happen?
> 
> I was able to trigger the crash on a real device (Banana Pi BPI-R4) but
> with a wrong swiotlb configuration. I do not have a strong opinion, I am
> fine to target net-next instead. What do you prefer?

I also don't have a strong opinion here.
But lean towards 'net' if you were able to trigger a crash.

> 
> Regards,
> Lorenzo
> 
> > What I am getting at, is that if not, it might be net-next material.
> > In either case, I have no objection to the change itself.
> > 
> > Reviewed-by: Simon Horman <horms@kernel.org>