linux-kernel - Re: [V1] mtd: devices: docg3:- Handle return value of devm

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Date:   Sun, 11 Dec 2016 20:15:39 +0100
From:   Marek Vasut <marek.vasut@...il.com>
To:     Arvind Yadav <arvind.yadav.cs@...il.com>, robert.jarzmik@...e.fr,
        dwmw2@...radead.org, computersforpeace@...il.com,
        boris.brezillon@...e-electrons.com, richard@....at,
        cyrille.pitchen@...el.com
Cc:     linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [V1] mtd: devices: docg3:- Handle return value of devm_ioremap.

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@...il.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