linux-kernel - Re: [PATCH] media: media/pci: prevent memory leak in bttv

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Date:   Fri, 17 Apr 2020 09:26:49 +0200
From:   Hans Verkuil <hverkuil-cisco@...all.nl>
To:     Xiaolong Huang <butterflyhuangxx@...il.com>, mchehab@...nel.org,
        tglx@...utronix.de, mpe@...erman.id.au, allison@...utok.net
Cc:     linux-media@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] media: media/pci: prevent memory leak in bttv_probe

On 25/03/2020 10:01, Xiaolong Huang wrote:
> In bttv_probe if some functions such as pci_enable_device,
> pci_set_dma_mask and request_mem_region fails the allocated
>  memory for btv should be released.
> 
> Signed-off-by: Xiaolong Huang <butterflyhuangxx@...il.com>
> ---
>  drivers/media/pci/bt8xx/bttv-driver.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/media/pci/bt8xx/bttv-driver.c b/drivers/media/pci/bt8xx/bttv-driver.c
> index a359da7773a9..37ac59110383 100644
> --- a/drivers/media/pci/bt8xx/bttv-driver.c
> +++ b/drivers/media/pci/bt8xx/bttv-driver.c
> @@ -4013,10 +4013,14 @@ static int bttv_probe(struct pci_dev *dev, const struct pci_device_id *pci_id)
>  	btv->id  = dev->device;
>  	if (pci_enable_device(dev)) {
>  		pr_warn("%d: Can't enable device\n", btv->c.nr);
> +		bttvs[btv->c.nr] = NULL;
> +		kfree(btv);
>  		return -EIO;

Let's change this...

>  	}
>  	if (pci_set_dma_mask(dev, DMA_BIT_MASK(32))) {
>  		pr_warn("%d: No suitable DMA available\n", btv->c.nr);
> +		bttvs[btv->c.nr] = NULL;
> +		kfree(btv);
>  		return -EIO;

this...

>  	}
>  	if (!request_mem_region(pci_resource_start(dev,0),
> @@ -4025,6 +4029,8 @@ static int bttv_probe(struct pci_dev *dev, const struct pci_device_id *pci_id)
>  		pr_warn("%d: can't request iomem (0x%llx)\n",
>  			btv->c.nr,
>  			(unsigned long long)pci_resource_start(dev, 0));
> +		bttvs[btv->c.nr] = NULL;
> +		kfree(btv);
>  		return -EBUSY;

and this to a goto free_mem.

>  	}
>  	pci_set_master(dev);
> @@ -4211,6 +4217,8 @@ static int bttv_probe(struct pci_dev *dev, const struct pci_device_id *pci_id)
>  	release_mem_region(pci_resource_start(btv->c.pci,0),
>  			   pci_resource_len(btv->c.pci,0));
>  	pci_disable_device(btv->c.pci);

And add the free_mem: label here.

> +	bttvs[btv->c.nr] = NULL;
> +	kfree(btv);
>  	return result;
>  }
>  
> 

Regards,

	Hans