Message-ID: <e91eb5b1-295e-1a21-d153-5e0fa52b2ffe@gmail.com>
Date:   Mon, 15 Nov 2021 11:30:53 +0300
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Subject: Re: [PATCH v2] can: etas_es58x: fix error handling
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To:     Johan Hovold <johan@kernel.org>
Cc:     mailhol.vincent@wanadoo.fr, wg@grandegger.com, mkl@pengutronix.de,
        davem@davemloft.net, kuba@kernel.org, linux-can@vger.kernel.org,
        netdev@vger.kernel.org, linux-kernel@vger.kernel.org
References: <CAMZ6Rq+orfUuUCCgeWyGc7P0vp3t-yjf_g9H=Jhk43f1zXGfDQ@mail.gmail.com>
 <20211115075124.17713-1-paskripkin@gmail.com>
 <YZIWT9ATzN611n43@hovoldconsulting.com>
 <7a98b159-f9bf-c0dd-f244-aec6c9a7dcaa@gmail.com>
 <YZIXdnFQcDcC2QvE@hovoldconsulting.com>
From:   Pavel Skripkin <paskripkin@gmail.com>
In-Reply-To: <YZIXdnFQcDcC2QvE@hovoldconsulting.com>
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On 11/15/21 11:16, Johan Hovold wrote:
> On Mon, Nov 15, 2021 at 11:15:07AM +0300, Pavel Skripkin wrote:
>> On 11/15/21 11:11, Johan Hovold wrote:
>> > Just a drive-by comment:
>> > 
>> > Are you sure about this move of the netdev[channel_idx] initialisation?
>> > What happens if the registered can device is opened before you
>> > initialise the pointer? NULL-deref in es58x_send_msg()?
>> > 
>> > You generally want the driver data fully initialised before you register
>> > the device so this looks broken.
>> > 
>> > And either way it is arguably an unrelated change that should go in a
>> > separate patch explaining why it is needed and safe.
>> > 
>> 
>> 
>> It was suggested by Vincent who is the maintainer of this driver [1].
> 
> Yeah, I saw that, but that doesn't necessarily mean it is correct.
> 
> You're still responsible for the changes you make and need to be able to
> argue why they are correct.
> 

Sure! I should have check it before sending v2 :( My bad, sorry. I see 
now, that there is possible calltrace which can hit NULL defer.

One thing I am wondering about is why in some code parts there are 
validation checks for es58x_dev->netdev[i] and in others they are missing.

Anyway, it's completely out of scope of current patch, I am going to 
resend v1 with fixed Fixes tag. Thank you for review!


With regards,
Pavel Skripkin