linux-kernel - Re: [PATCH RESEND 3/4] pinctrl: at91: Prevent NULL dereference if of_match_device returns NULL

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Date:	Fri, 16 Nov 2012 09:36:39 +0100
From:	Nicolas Ferre <nicolas.ferre@...el.com>
To:	Jean-Christophe PLAGNIOL-VILLARD <plagnioj@...osoft.com>,
	Axel Lin <axel.lin@...ics.com>,
	Linus Walleij <linus.walleij@...aro.org>
CC:	<linux-kernel@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH RESEND 3/4] pinctrl: at91: Prevent NULL dereference if
 of_match_device returns NULL

On 11/15/2012 11:00 AM, Jean-Christophe PLAGNIOL-VILLARD :
> On 12:58 Thu 15 Nov     , Axel Lin wrote:
>> of_match_device() may return NULL.
> this is not possible on at91
> 
> and I do a oups here as if we have a NULL pointer which means the driver is
> wrong

Well, okay, but it does not prevent from adding a supplementary check to
mimic every other pinctrl driver and use a common return path to the
of_match_device() function.

So I am not completely against this patch (that I why I added my Acked-by).

>> Signed-off-by: Axel Lin <axel.lin@...ics.com>
>> ---
>> This resend CC Jean-Christophe.
>>
>>  drivers/pinctrl/pinctrl-at91.c |   17 +++++++++++++----
>>  1 file changed, 13 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/pinctrl/pinctrl-at91.c b/drivers/pinctrl/pinctrl-at91.c
>> index 8490a55..32006c8 100644
>> --- a/drivers/pinctrl/pinctrl-at91.c
>> +++ b/drivers/pinctrl/pinctrl-at91.c
>> @@ -829,13 +829,18 @@ static int __devinit at91_pinctrl_probe_dt(struct platform_device *pdev,
>>  	uint32_t *tmp;
>>  	struct device_node *np = pdev->dev.of_node;
>>  	struct device_node *child;
>> +	const struct of_device_id *match;
>>  
>>  	if (!np)
>>  		return -ENODEV;
>>  
>> +	match = of_match_device(at91_pinctrl_of_match, &pdev->dev)->data;
>> +	if (!match)
>> +		return -ENODEV;
>> +
>>  	info->dev = &pdev->dev;
>> -	info->ops = (struct at91_pinctrl_mux_ops*)
>> -		of_match_device(at91_pinctrl_of_match, &pdev->dev)->data;
>> +	info->ops = (struct at91_pinctrl_mux_ops *) match->data;
>> +
>>  	at91_pinctrl_child_count(info, np);
>>  
>>  	if (info->nbanks < 1) {
>> @@ -1359,6 +1364,7 @@ static struct of_device_id at91_gpio_of_match[] __devinitdata = {
>>  static int __devinit at91_gpio_probe(struct platform_device *pdev)
>>  {
>>  	struct device_node *np = pdev->dev.of_node;
>> +	const struct of_device_id *match;
>>  	struct resource *res;
>>  	struct at91_gpio_chip *at91_chip = NULL;
>>  	struct gpio_chip *chip;
>> @@ -1399,8 +1405,11 @@ static int __devinit at91_gpio_probe(struct platform_device *pdev)
>>  		goto err;
>>  	}
>>  
>> -	at91_chip->ops = (struct at91_pinctrl_mux_ops*)
>> -		of_match_device(at91_gpio_of_match, &pdev->dev)->data;
>> +	match = of_match_device(at91_gpio_of_match, &pdev->dev);
>> +	if (!match)
>> +		return -ENODEV;
>> +
>> +	at91_chip->ops = (struct at91_pinctrl_mux_ops *) match->data;
>>  	at91_chip->pioc_virq = irq;
>>  	at91_chip->pioc_idx = alias_idx;
>>  
>> -- 
>> 1.7.9.5
>>
>>
>>
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@...ts.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 
> 

-- 
Nicolas Ferre
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