Re: [PATCH] BUG: pinmux: forbid mux_usecount to be set at UINT_MAX

[Richard Genoud]

2013/3/20 Stephen Warren <swarren@xxxxxxxxxxxxx>:
> On 03/20/2013 05:31 AM, Richard Genoud wrote:
>> If pin_free is called on a pin already freed, mux_usecount is set to
>> UINT_MAX which is really a bad idea.
>> This will silently ignore a double call to pin_free
>
> Shouldn't we WARN_ON(this case)?
yes indeed, it may be better to issue a big warning because AFAIK
that's not normal.

>
>> diff --git a/drivers/pinctrl/pinmux.c b/drivers/pinctrl/pinmux.c
>
>>       if (!gpio_range) {
>> -             desc->mux_usecount--;
>> -             if (desc->mux_usecount)
>> +             if (1 == desc->mux_usecount)
>> +                     desc->mux_usecount = 0;
>> +             else
>>                       return NULL;
>
> What if desc-mux_usecount was 2; this patch prevents the use-count from
> being decremented to 1 in this case. Shouldn't this be:
>
>         if (!gpio_range) {
> +               if (WARN_ON(!desc->mux_usecount))
> +                       return NULL;
>                 desc->mux_usecount--;
>
Well, I'm not very familiar with this code, but can mux_usecount be
higher than 1 ?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/