linux-kernel - Re: [RFC/RFT PATCH] pinctrl: bcm2835: don't -EINVAL on alternate funcs from get

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAMRc=MdEcjFUp2OEutcnDqSHbbait3f25NEWbdp7mARyKZLvBw@mail.gmail.com>
Date: Wed, 19 Feb 2025 15:29:59 +0100
From: Bartosz Golaszewski <brgl@...ev.pl>
To: Mark Brown <broonie@...nel.org>
Cc: Linus Walleij <linus.walleij@...aro.org>, 
	Florian Fainelli <florian.fainelli@...adcom.com>, Ray Jui <rjui@...adcom.com>, 
	Scott Branden <sbranden@...adcom.com>, 
	Broadcom internal kernel review list <bcm-kernel-feedback-list@...adcom.com>, Stefan Wahren <wahrenst@....net>, 
	Liao Chen <liaochen4@...wei.com>, Chen-Yu Tsai <wens@...e.org>, 
	Marek Szyprowski <m.szyprowski@...sung.com>, linux-gpio@...r.kernel.org, 
	linux-rpi-kernel@...ts.infradead.org, linux-arm-kernel@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, 
	Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: Re: [RFC/RFT PATCH] pinctrl: bcm2835: don't -EINVAL on alternate
 funcs from get_direction()

On Wed, Feb 19, 2025 at 3:27 PM Mark Brown <broonie@...nel.org> wrote:
>
> On Wed, Feb 19, 2025 at 11:27:50AM +0100, Bartosz Golaszewski wrote:
> > From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
> >
> > Since commit 9d846b1aebbe ("gpiolib: check the return value of
> > gpio_chip::get_direction()") we check the return value of the
> > get_direction() callback as per its API contract. This driver returns
> > -EINVAL if the pin in question is set to one of the alternative
> > (non-GPIO) functions. This isn't really an error that should be
> > communicated to GPIOLIB so default to returning the "safe" value of
> > INPUT in this case. The GPIO subsystem does not have the notion of
> > "unknown" direction.
>
> I see this was already tested for these specific boards.  I've also
> found that Avenger96 is failing with bisect pointing to the same commit
> this is fixing:
>
>     https://lava.sirena.org.uk/scheduler/job/1126314
>
> as is the Libretech Potato:
>
>     https://lava.sirena.org.uk/scheduler/job/1126285
>
> neither of which produce any output before dying, they'll not be fixed
> by this change.  Seems like an audit of the drivers might be in order?

Right. I don't know if they return EINVAL or some other error so let
me prepare a change that will not bail-out but simply warn on
get_direction() errors in gpiochip_add_data() instead.

This patch can still go upstream IMO.

Bart