linux-kernel - Re: [PATCH 2/3] PCI/pwrctrl: Fix device and OF node leak at bus scan

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Message-ID: <20250722110833.0000542d@huawei.com>
Date: Tue, 22 Jul 2025 11:08:33 +0100
From: Jonathan Cameron <Jonathan.Cameron@...wei.com>
To: Johan Hovold <johan+linaro@...nel.org>
CC: Bjorn Helgaas <bhelgaas@...gle.com>, Manivannan Sadhasivam
	<mani@...nel.org>, <linux-pci@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <stable@...r.kernel.org>
Subject: Re: [PATCH 2/3] PCI/pwrctrl: Fix device and OF node leak at bus
 scan

On Mon, 21 Jul 2025 17:36:08 +0200
Johan Hovold <johan+linaro@...nel.org> wrote:

> Make sure to drop the references to the pwrctrl OF node and device taken
> by of_pci_find_child_device() and of_find_device_by_node() respectively
> when scanning the bus.
> 
> Fixes: 957f40d039a9 ("PCI/pwrctrl: Move creation of pwrctrl devices to pci_scan_device()")
> Cc: stable@...r.kernel.org	# 6.15
> Cc: Manivannan Sadhasivam <mani@...nel.org>
> Signed-off-by: Johan Hovold <johan+linaro@...nel.org>

Similar to previous, I'd use a new DEFINE_FREE for the platform device and
the infrastructure is already in place for the for the of_node
(and used a lot in the core DT code).

One other comment inline.


> ---
>  drivers/pci/probe.c | 19 ++++++++++++++++---
>  1 file changed, 16 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index 4b8693ec9e4c..c5f59de790c7 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -2515,9 +2515,15 @@ static struct platform_device *pci_pwrctrl_create_device(struct pci_bus *bus, in
>  	struct device_node *np;
>  
>  	np = of_pci_find_child_device(dev_of_node(&bus->dev), devfn);
> -	if (!np || of_find_device_by_node(np))
> +	if (!np)
>  		return NULL;
>  
> +	pdev = of_find_device_by_node(np);
Given we have two entirely different pdevs in here, I'd use an extra
local variable to indicate what this one is the pwctrl one created below.

> +	if (pdev) {
> +		put_device(&pdev->dev);
> +		goto err_put_of_node;
> +	}
> +
>  	/*
>  	 * First check whether the pwrctrl device really needs to be created or
>  	 * not. This is decided based on at least one of the power supplies
> @@ -2525,17 +2531,24 @@ static struct platform_device *pci_pwrctrl_create_device(struct pci_bus *bus, in
>  	 */
>  	if (!of_pci_supply_present(np)) {
>  		pr_debug("PCI/pwrctrl: Skipping OF node: %s\n", np->name);
> -		return NULL;
> +		goto err_put_of_node;
>  	}
>  
>  	/* Now create the pwrctrl device */
>  	pdev = of_platform_device_create(np, NULL, &host->dev);
>  	if (!pdev) {
>  		pr_err("PCI/pwrctrl: Failed to create pwrctrl device for node: %s\n", np->name);
> -		return NULL;
> +		goto err_put_of_node;
>  	}
>  
> +	of_node_put(np);
> +
>  	return pdev;
> +
> +err_put_of_node:
> +	of_node_put(np);
> +
> +	return NULL;
>  }
>  
>  /*