linux-kernel - Re: [PATCH] gpio: don't use same lockdep class for all devm_gpiochip_add

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] [day] [month] [year] [list]

Date:   Tue, 4 Aug 2020 01:23:11 +0200
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Ahmad Fatoum <a.fatoum@...gutronix.de>
Cc:     Bartosz Golaszewski <bgolaszewski@...libre.com>,
        Grygorii Strashko <grygorii.strashko@...com>,
        Thierry Reding <treding@...dia.com>,
        Sascha Hauer <kernel@...gutronix.de>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] gpio: don't use same lockdep class for all
 devm_gpiochip_add_data users

On Fri, Jul 31, 2020 at 2:39 PM Ahmad Fatoum <a.fatoum@...gutronix.de> wrote:

> Commit 959bc7b22bd2 ("gpio: Automatically add lockdep keys") documents
> in its commits message its intention to "create a unique class key for
> each driver".
>
> It does so by having gpiochip_add_data add in-place the definition of
> two static lockdep classes for LOCKDEP use. That way, every caller of
> the macro adds their gpiochip with unique lockdep classes.
>
> There are many indirect callers of gpiochip_add_data, however, via
> use of devm_gpiochip_add_data. devm_gpiochip_add_data has external
> linkage and all its users will share the same lockdep classes, which
> probably is not intended.
>
> Fix this by replicating the gpio_chip_add_data statics-in-macro for
> the devm_ version as well.
>
> Fixes: 959bc7b22bd2 ("gpio: Automatically add lockdep keys")
> Signed-off-by: Ahmad Fatoum <a.fatoum@...gutronix.de>
> ---
> This doesn't fix any particular problem I ran into, but the code
> looked buggy, at least to my lockdep-user-not-developer eyes.

Thanks patch applied, I think we had this fixed before
but managed to loose it in some API rewrite. Thanks for
fixing it up!

Yours,
Linus Walleij