Re: [PATCH v2] can: etas_es58x: fix error handling

On Mon. 15 Nov 2021 at 17:30, Pavel Skripkin [off-list ref] wrote:

On 11/15/21 11:16, Johan Hovold wrote:

quoted

On Mon, Nov 15, 2021 at 11:15:07AM +0300, Pavel Skripkin wrote:

quoted

On 11/15/21 11:11, Johan Hovold wrote:

quoted

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?