linux-kernel - Re: [PATCH] drm/bridge: fix RC

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]

Date:   Fri, 19 Jul 2019 10:33:59 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Andrzej Hajda <a.hajda@...sung.com>
Cc:     David Airlie <airlied@...ux.ie>, Daniel Vetter <daniel@...ll.ch>,
        Ronald Tschalär <ronald@...ovation.ch>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Sean Paul <sean@...rly.run>,
        dri-devel <dri-devel@...ts.freedesktop.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] drm/bridge: fix RC_CORE dependency

On Fri, Jul 19, 2019 at 9:01 AM Andrzej Hajda <a.hajda@...sung.com> wrote:
>
> On 18.07.2019 15:42, Arnd Bergmann wrote:
> > Using 'imply' causes a new problem, as it allows the case of
> > CONFIG_INPUT=m with RC_CORE=y, which fails to link:
>
>
> I have reviewed dependencies and I wonder how such configuration is
> possible at all.
>
> RC_CORE depends on INPUT (at least on today's next branch) so if INPUT=m
> then RC_CORE should be either n either m, am I right?

Right.

> Arnd, are there unknown to me changes in RC/INPUT dependencies?

I think this is 'imply' behaving oddly when we have conflicting requirements:

- INPUT=m forces RC_CORE to be =m or =n
- DRM_SIL_SII8620=y asks RC_CORE to be =y unless it cannot be enabled

Kconfig decided to make this RC_CORE=y, which caused the link
failure. Making it RC_CORE=m however would not work either because
then we'd get a link failure from the sii8620 driver to rc_core.

so a pure 'imply' cannot work here, and we need a dependency, one of:

a)
   depends on INPUT || !INPUT
   select RC_CORE if INPUT

b) depends on RC_CORE || !RC_CORE

b) is what othe drivers use, e.g. SMS_SDIO_DRV

       Arnd