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From: Vincent MAILHOL <mailhol.vincent@wanadoo.fr>
To: Pavel Skripkin <paskripkin@gmail.com>
Cc: Johan Hovold <johan@kernel.org>,
	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
Subject: Re: [PATCH v2] can: etas_es58x: fix error handling
Date: Mon, 15 Nov 2021 18:24:22 +0900	[thread overview]
Message-ID: <CAMZ6Rq+3uPE31q=HN-BdkXsMYZf53=VfNSn0OD6HcweLO0u-_Q@mail.gmail.com> (raw)
In-Reply-To: <e91eb5b1-295e-1a21-d153-5e0fa52b2ffe@gmail.com>

On Mon. 15 Nov 2021 at 17:30, Pavel Skripkin <paskripkin@gmail.com> wrote:
> 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.

I should be the one apologizing here. Sorry for the confusion.

> 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.

There is a validation when it is accessed in a for loop.
It is not guarded in es58x_send_msg() because this function
expects the channel_idx to be a valid index.

Does this answer your wonders?

  reply	other threads:[~2021-11-15  9:25 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-11-14 20:58 [PATCH] can: etas_es58x: fix error handling Pavel Skripkin
2021-11-15  5:27 ` Vincent MAILHOL
2021-11-15  7:40   ` Pavel Skripkin
2021-11-15  7:51   ` [PATCH v2] " Pavel Skripkin
2021-11-15  8:11     ` Johan Hovold
2021-11-15  8:15       ` Pavel Skripkin
2021-11-15  8:16         ` Johan Hovold
2021-11-15  8:30           ` Pavel Skripkin
2021-11-15  9:24             ` Vincent MAILHOL [this message]
2021-11-15  9:26               ` Pavel Skripkin
2021-11-15  8:37       ` [PATCH v3] " Pavel Skripkin
2021-11-15  9:15         ` Vincent MAILHOL

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