Re: [PATCH v3] [BUGFIX] gpio: reject invalid gpio before getting gpio_desc

From: Linus Walleij
Date: Mon Aug 07 2017 - 08:01:04 EST

On Wed, Aug 2, 2017 at 6:47 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>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> ---
> Changes in v3:
> - Remove unneeded empty lines.

Patch applied for fixes.

Linus Walleij