linux-kernel - Re: [PATCH] mtd: rawnand: denali: Fix a possible resource leak in denali_pci

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Date:   Mon, 1 Aug 2022 20:26:07 +0200
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     "GONG, Ruiqi" <gongruiqi1@...wei.com>, miquel.raynal@...tlin.com,
        richard@....at, vigneshr@...com
Cc:     linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org,
        wangweiyang2@...wei.com
Subject: Re: [PATCH] mtd: rawnand: denali: Fix a possible resource leak in
 denali_pci_probe

Le 01/08/2022 à 10:03, GONG, Ruiqi a écrit :
> Call pci_release_regions() to retrieve the allocated resource when
> devm_ioremap() or denali_init() failed.
> 

Hi,
this is not correct.

First, should you be right, you should also update the .remove() 
function the same way.

Second, at the beginning there is pcim_enable_device() call.
This looked like magic to me when I first saw it, but this function 
makes some pci_ functions work just as it they were pcim_ functions.

See pcim_enable_device() ([1]), at line 2132.
When pcim_release() ([2]) is called by the framework, then regions are 
released at line 2079

CJ

[1]: https://elixir.bootlin.com/linux/v5.19/source/drivers/pci/pci.c#L2118
[2]: https://elixir.bootlin.com/linux/v5.19/source/drivers/pci/pci.c#L2071

> Signed-off-by: GONG, Ruiqi <gongruiqi1@...wei.com>
> ---
>   drivers/mtd/nand/raw/denali_pci.c | 9 ++++++---
>   1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/denali_pci.c b/drivers/mtd/nand/raw/denali_pci.c
> index de7e722d3826..40943cda0914 100644
> --- a/drivers/mtd/nand/raw/denali_pci.c
> +++ b/drivers/mtd/nand/raw/denali_pci.c
> @@ -74,21 +74,22 @@ static int denali_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
>   		return ret;
>   	}
>   
> +	ret = -ENOMEM;
>   	denali->reg = devm_ioremap(denali->dev, csr_base, csr_len);
>   	if (!denali->reg) {
>   		dev_err(&dev->dev, "Spectra: Unable to remap memory region\n");
> -		return -ENOMEM;
> +		goto out_release_pci;
>   	}
>   
>   	denali->host = devm_ioremap(denali->dev, mem_base, mem_len);
>   	if (!denali->host) {
>   		dev_err(&dev->dev, "Spectra: ioremap failed!");
> -		return -ENOMEM;
> +		goto out_release_pci;
>   	}
>   
>   	ret = denali_init(denali);
>   	if (ret)
> -		return ret;
> +		goto out_release_pci;
>   
>   	nsels = denali->nbanks;
>   
> @@ -116,6 +117,8 @@ static int denali_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
>   
>   out_remove_denali:
>   	denali_remove(denali);
> +out_release_pci:
> +	pci_release_regions(dev);
>   	return ret;
>   }
>