Re: [PATCH v3 2/4] serial: mctrl_gpio: Add a NULL check to mctrl_gpio_to_gpiod()

Uwe Kleine-König
2019-08-02T12:12:38Z

On Fri, Aug 02, 2019 at 10:04:10AM +0000, Schrempf Frieder wrote:
> From: Frieder Schrempf <frieder.schrempf@kontron.de>
>
> As it is allowed to use the mctrl_gpio_* functions before
> initialization (as the 8250 driver does according to 434be0ae7aa7),

Actually I was surprised some time ago that 8250 used serial_mctrl
without first initializing it and expecting it to work. I didn't look in
detail, but I wouldn't go so far to call this "allowed". The commit
itself calls it "workaround" which seems a better match.

> it seems appropriate to have a NULL check in all of the functions.
> Otherwise the mctrl_gpio_to_gpiod() function is prone to be used
> in a context that can lead to a NULL pointer dereference.
>
> Signed-off-by: Frieder Schrempf <frieder.schrempf@kontron.de>

Best regards
Uwe

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