linux-kernel - Re: [PATCH v2] [BUGFIX] gpio: reject invalid gpio before getting gpio

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Date:   Tue, 1 Aug 2017 10:09:09 +0200
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Masami Hiramatsu <mhiramat@...nel.org>
Cc:     "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Masami Hiramatsu <masami.hiramatsu@...aro.org>,
        Jassi Brar <jaswinder.singh@...aro.org>
Subject: Re: [PATCH v2] [BUGFIX] gpio: reject invalid gpio before getting gpio_desc

On Mon, Jul 31, 2017 at 3:57 AM, Masami Hiramatsu <mhiramat@...nel.org> wrote:

> Check user-given gpio number and reject it before
> calling gpio_to_desc() because gpio_to_desc() is
> for kernel driver and it expects given gpio number
> is valid (means 0 to 511).
> If given number is invalid, gpio_to_desc() calls
> WARN() and dump registers and stack for debug.
> This means user can easily kick WARN() just by
> writing invalid gpio number (e.g. 512) to
> /sys/class/gpio/export.
>
> Fixes: 0e9a5edf5d01 ("gpio: fix deferred probe detection for legacy API")
> Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
> ---
>   Changes in v2:
>    - Add gpio_to_valid_desc() according to Andy's comment (Thanks!).
>    - Fix patch description.

I hate the old sysfs ABI sigh. Thanks for fixing it anyways!

Should this be tagged for stable?

Waiting for Andy's review before applying.

Yours,
Linus Walleij