Re: [PATCH v2] [BUGFIX] gpio: reject invalid gpio before getting gpio_desc

From: Linus Walleij
Date: Tue Aug 01 2017 - 04:09:19 EST

On Mon, Jul 31, 2017 at 3:57 AM, Masami Hiramatsu <mhiramat@xxxxxxxxxx> 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@xxxxxxxxxx>
> ---
> 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.

Linus Walleij