linux-kernel - Re: [PATCH 1/2] PCI: of: Fix memory leak when of_changeset_create

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Message-ID: <20230928092657.5e575202@bootlin.com>
Date:   Thu, 28 Sep 2023 09:26:57 +0200
From:   Herve Codina <herve.codina@...tlin.com>
To:     Lizhi Hou <lizhi.hou@....com>
Cc:     <linux-pci@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <Jonathan.Cameron@...wei.com>,
        <bhelgaas@...gle.com>, <robh@...nel.org>
Subject: Re: [PATCH 1/2] PCI: of: Fix memory leak when
 of_changeset_create_node() failed

Hi Lizhi,

On Fri, 15 Sep 2023 11:08:06 -0700
Lizhi Hou <lizhi.hou@....com> wrote:

> Destroy and free cset when failure happens.
> 
> Fixes: 407d1a51921e ("PCI: Create device tree node for bridge")
> Reported-by: Herve Codina <herve.codina@...tlin.com>
> Closes: https://lore.kernel.org/all/20230911171319.495bb837@bootlin.com/
> Signed-off-by: Lizhi Hou <lizhi.hou@....com>
> ---
>  drivers/pci/of.c | 19 +++++++++++--------
>  1 file changed, 11 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/pci/of.c b/drivers/pci/of.c
> index 2af64bcb7da3..498b5cae8bca 100644
> --- a/drivers/pci/of.c
> +++ b/drivers/pci/of.c
> @@ -657,30 +657,33 @@ void of_pci_make_dev_node(struct pci_dev *pdev)
>  
>  	cset = kmalloc(sizeof(*cset), GFP_KERNEL);
>  	if (!cset)
> -		goto failed;
> +		goto failed_alloc_cset;

Usually goto labels indicate what the goto does instead of where we come
from.
https://elixir.bootlin.com/linux/v6.5/source/Documentation/process/coding-style.rst#L536

In this case, it should be "goto failed_free_name".

>  	of_changeset_init(cset);
>  
>  	np = of_changeset_create_node(cset, ppnode, name);
>  	if (!np)
> -		goto failed;
> -	np->data = cset;
> +		goto failed_create_node;

same comment

>  
>  	ret = of_pci_add_properties(pdev, cset, np);
>  	if (ret)
> -		goto failed;
> +		goto failed_add_prop;

same comment

>  
>  	ret = of_changeset_apply(cset);
>  	if (ret)
> -		goto failed;
> +		goto failed_add_prop;

same comment

>  
> +	np->data = cset;
>  	pdev->dev.of_node = np;
>  	kfree(name);
>  
>  	return;
>  
> -failed:
> -	if (np)
> -		of_node_put(np);
> +failed_add_prop:
> +	of_node_put(np);
> +failed_create_node:
> +	of_changeset_destroy(cset);
> +	kfree(cset);
> +failed_alloc_cset:
>  	kfree(name);
>  }
>  #endif

Best regards,
Hervé