linux-kernel - Re: [PATCH] drivers/uio/uio_pdrv_genirq.c: Fix memory leak & confusing labels

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Date:	Wed, 28 Nov 2012 00:07:47 +0100
From:	"Hans J. Koch" <hjk@...sjkoch.de>
To:	Vitalii Demianets <vitas@...factor.kiev.ua>
Cc:	linux-kernel@...r.kernel.org, "Hans J. Koch" <hjk@...sjkoch.de>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [PATCH] drivers/uio/uio_pdrv_genirq.c: Fix memory leak &
 confusing labels

On Tue, Nov 27, 2012 at 07:29:32PM +0200, Vitalii Demianets wrote:
> Memory leak was caused by jumping to the wrong exit label. So, it is good time
> to improve misleading label names too.

I agree that bad0, bad1, and bad2 are not the best choice for label names...
I don't have any objections to your renaming.

But there's a more serious bug, maybe you can fix that as well while you're
at it? (See below)

Thanks,
Hans

> 
> Signed-off-by: Vitalii Demianets <vitas@...factor.kiev.ua>
> ---
>  drivers/uio/uio_pdrv_genirq.c |   21 +++++++++++----------
>  1 files changed, 11 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/uio/uio_pdrv_genirq.c b/drivers/uio/uio_pdrv_genirq.c
> index 42202cd..b88cf7b 100644
> --- a/drivers/uio/uio_pdrv_genirq.c
> +++ b/drivers/uio/uio_pdrv_genirq.c
> @@ -110,7 +110,7 @@ static int uio_pdrv_genirq_probe(struct platform_device *pdev)
>  		if (!uioinfo) {
>  			ret = -ENOMEM;
>  			dev_err(&pdev->dev, "unable to kmalloc\n");
> -			goto bad2;
> +			goto out;
>  		}
>  		uioinfo->name = pdev->dev.of_node->name;
>  		uioinfo->version = "devicetree";
> @@ -125,20 +125,20 @@ static int uio_pdrv_genirq_probe(struct platform_device *pdev)
>  
>  	if (!uioinfo || !uioinfo->name || !uioinfo->version) {
>  		dev_err(&pdev->dev, "missing platform_data\n");
> -		goto bad0;
> +		goto out_uioinfo;
>  	}
>  
>  	if (uioinfo->handler || uioinfo->irqcontrol ||
>  	    uioinfo->irq_flags & IRQF_SHARED) {
>  		dev_err(&pdev->dev, "interrupt configuration error\n");
> -		goto bad0;
> +		goto out_uioinfo;
>  	}
>  
>  	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
>  	if (!priv) {
>  		ret = -ENOMEM;
>  		dev_err(&pdev->dev, "unable to kmalloc\n");
> -		goto bad0;
> +		goto out_uioinfo;
>  	}
>  
>  	priv->uioinfo = uioinfo;
> @@ -150,7 +150,7 @@ static int uio_pdrv_genirq_probe(struct platform_device *pdev)
>  		ret = platform_get_irq(pdev, 0);
>  		if (ret < 0) {
>  			dev_err(&pdev->dev, "failed to get IRQ\n");
> -			goto bad0;
> +			goto out_priv;
>  		}
>  		uioinfo->irq = ret;
>  	}
> @@ -205,19 +205,20 @@ static int uio_pdrv_genirq_probe(struct platform_device *pdev)
>  	ret = uio_register_device(&pdev->dev, priv->uioinfo);
>  	if (ret) {
>  		dev_err(&pdev->dev, "unable to register uio device\n");
> -		goto bad1;
> +		goto out_pm;
>  	}
>  
>  	platform_set_drvdata(pdev, priv);
>  	return 0;
> - bad1:
> -	kfree(priv);
> +out_pm:
>  	pm_runtime_disable(&pdev->dev);
> - bad0:
> +out_priv:
> +	kfree(priv);
> +out_uioinfo:
>  	/* kfree uioinfo for OF */
>  	if (pdev->dev.of_node)
>  		kfree(uioinfo);

The free() depends on pdev->dev.of_node, while the allocation doesn't!!!!
That's another source of memory leaks.

> - bad2:
> +out:
>  	return ret;
>  }
>  
> -- 
> 1.7.8.6
> 
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