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[V1] mtd: devices: docg3:- Handle return value of devm_ioremap.

Started byArvind Yadav <arvind.yadav.cs@gmail.com>
First post2016-12-11 19:10 +0100
Last post2016-12-12 19:20 +0100
Articles 4 — 4 participants

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  [V1] mtd: devices: docg3:- Handle return value of devm_ioremap. Arvind Yadav <arvind.yadav.cs@gmail.com> - 2016-12-11 19:10 +0100
    Re: [V1] mtd: devices: docg3:- Handle return value of devm_ioremap. Marek Vasut <marek.vasut@gmail.com> - 2016-12-11 20:20 +0100
      Re: [V1] mtd: devices: docg3:- Handle return value of devm_ioremap. arvind Yadav <arvind.yadav.cs@gmail.com> - 2016-12-12 04:00 +0100
      Re: [V1] mtd: devices: docg3:- Handle return value of devm_ioremap. Fabio Estevam <festevam@gmail.com> - 2016-12-12 19:20 +0100

#1540050 — [V1] mtd: devices: docg3:- Handle return value of devm_ioremap.

FromArvind Yadav <arvind.yadav.cs@gmail.com>
Date2016-12-11 19:10 +0100
Subject[V1] mtd: devices: docg3:- Handle return value of devm_ioremap.
Message-ID<sNgJs-2lO-27@gated-at.bofh.it>
Here, If devm_ioremap will fail. It will return NULL.
Kernel can run into a NULL-pointer dereference.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
---
 drivers/mtd/devices/docg3.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
index b833e6c..013b5b9 100644
--- a/drivers/mtd/devices/docg3.c
+++ b/drivers/mtd/devices/docg3.c
@@ -2083,9 +2083,12 @@ static int __init docg3_probe(struct platform_device *pdev)
 		dev_err(dev, "No I/O memory resource defined\n");
 		return ret;
 	}
-	base = devm_ioremap(dev, ress->start, DOC_IOSPACE_SIZE);
 
 	ret = -ENOMEM;
+	base = devm_ioremap(dev, ress->start, DOC_IOSPACE_SIZE);
+	if (!base)
+		return ret;
+
 	cascade = devm_kzalloc(dev, sizeof(*cascade) * DOC_MAX_NBFLOORS,
 			       GFP_KERNEL);
 	if (!cascade)
-- 
2.7.4

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#1540052

FromMarek Vasut <marek.vasut@gmail.com>
Date2016-12-11 20:20 +0100
Message-ID<sNhPb-2YZ-5@gated-at.bofh.it>
In reply to#1540050
On 12/11/2016 07:01 PM, Arvind Yadav wrote:
> Here, If devm_ioremap will fail. It will return NULL.
> Kernel can run into a NULL-pointer dereference.
> 
> Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
> ---
>  drivers/mtd/devices/docg3.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
> index b833e6c..013b5b9 100644
> --- a/drivers/mtd/devices/docg3.c
> +++ b/drivers/mtd/devices/docg3.c
> @@ -2083,9 +2083,12 @@ static int __init docg3_probe(struct platform_device *pdev)
>  		dev_err(dev, "No I/O memory resource defined\n");
>  		return ret;
>  	}
> -	base = devm_ioremap(dev, ress->start, DOC_IOSPACE_SIZE);
>  
>  	ret = -ENOMEM;
> +	base = devm_ioremap(dev, ress->start, DOC_IOSPACE_SIZE);
> +	if (!base)
> +		return ret;

I think return -ENOMEM right away won't hurt here. Also, dev_err()
explaining the failure would be nice to add.

Thanks!

>  	cascade = devm_kzalloc(dev, sizeof(*cascade) * DOC_MAX_NBFLOORS,
>  			       GFP_KERNEL);
>  	if (!cascade)
> 


-- 
Best regards,
Marek Vasut

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#1540119

Fromarvind Yadav <arvind.yadav.cs@gmail.com>
Date2016-12-12 04:00 +0100
Message-ID<sNp0l-743-7@gated-at.bofh.it>
In reply to#1540052
Yes, We are returning -ENOMEM, ret is initialized to -ENOMEM.
As per your concern, I have added dev_err failure message.

Thanks
-Arvind

On Monday 12 December 2016 12:45 AM, Marek Vasut wrote:
> On 12/11/2016 07:01 PM, Arvind Yadav wrote:
>> Here, If devm_ioremap will fail. It will return NULL.
>> Kernel can run into a NULL-pointer dereference.
>>
>> Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
>> ---
>>   drivers/mtd/devices/docg3.c | 5 ++++-
>>   1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mtd/devices/docg3.c b/drivers/mtd/devices/docg3.c
>> index b833e6c..013b5b9 100644
>> --- a/drivers/mtd/devices/docg3.c
>> +++ b/drivers/mtd/devices/docg3.c
>> @@ -2083,9 +2083,12 @@ static int __init docg3_probe(struct platform_device *pdev)
>>   		dev_err(dev, "No I/O memory resource defined\n");
>>   		return ret;
>>   	}
>> -	base = devm_ioremap(dev, ress->start, DOC_IOSPACE_SIZE);
>>   
>>   	ret = -ENOMEM;
>> +	base = devm_ioremap(dev, ress->start, DOC_IOSPACE_SIZE);
>> +	if (!base)
>> +		return ret;
> I think return -ENOMEM right away won't hurt here. Also, dev_err()
> explaining the failure would be nice to add.
>
> Thanks!
>
>>   	cascade = devm_kzalloc(dev, sizeof(*cascade) * DOC_MAX_NBFLOORS,
>>   			       GFP_KERNEL);
>>   	if (!cascade)
>>
>

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#1540507

FromFabio Estevam <festevam@gmail.com>
Date2016-12-12 19:20 +0100
Message-ID<sNDmF-7Fp-27@gated-at.bofh.it>
In reply to#1540052
On Sun, Dec 11, 2016 at 5:15 PM, Marek Vasut <marek.vasut@gmail.com> wrote:

>>       ret = -ENOMEM;
>> +     base = devm_ioremap(dev, ress->start, DOC_IOSPACE_SIZE);
>> +     if (!base)
>> +             return ret;
>
> I think return -ENOMEM right away won't hurt here. Also, dev_err()
> explaining the failure would be nice to add.

There is no need to add dev_err() message as the mm core will complain
loudly if devm_ioremap() fails.

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