linux-kernel - Re: [PATCH] bus: hisi_lpc: fix missing platform_device_put() in hisi_lpc_acpi

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Date:   Mon, 4 Jul 2022 09:01:37 +0100
From:   John Garry <john.garry@...wei.com>
To:     Yang Yingliang <yangyingliang@...wei.com>,
        <linux-kernel@...r.kernel.org>
CC:     "andriy.shevchenko@...ux.intel.com >> Andy Shevchenko" 
        <andriy.shevchenko@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J. Wysocki" <rafael@...nel.org>
Subject: Re: [PATCH] bus: hisi_lpc: fix missing platform_device_put() in
 hisi_lpc_acpi_probe()

On 01/07/2022 10:43, Yang Yingliang wrote:

+

Please send any updated version cc'ing Rafael, who kindly offered to 
pick up this patch

> In error case in hisi_lpc_acpi_probe() after calling platform_device_add(),
> hisi_lpc_acpi_remove() can't release the failed 'pdev', so it will be leak,
> call platform_device_put() to fix this problem.
> I'v constructed this error case and tested this patch on D05 board.
> 
> Fixes: 99c0228d6ff1 ("HISI LPC: Re-Add ACPI child enumeration support")
> Reported-by: Hulk Robot <hulkci@...wei.com>
> Signed-off-by: Yang Yingliang <yangyingliang@...wei.com>
> ---
>   drivers/bus/hisi_lpc.c | 10 ++++++----
>   1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/bus/hisi_lpc.c b/drivers/bus/hisi_lpc.c
> index 378f5d62a991..e7eaa8784fee 100644
> --- a/drivers/bus/hisi_lpc.c
> +++ b/drivers/bus/hisi_lpc.c
> @@ -503,13 +503,13 @@ static int hisi_lpc_acpi_probe(struct device *hostdev)
>   {
>   	struct acpi_device *adev = ACPI_COMPANION(hostdev);
>   	struct acpi_device *child;
> +	struct platform_device *pdev;

nit: please maintain reverse-firtree ordering

>   	int ret;
>   
>   	/* Only consider the children of the host */
>   	list_for_each_entry(child, &adev->children, node) {
>   		const char *hid = acpi_device_hid(child);
>   		const struct hisi_lpc_acpi_cell *cell;
> -		struct platform_device *pdev;
>   		const struct resource *res;
>   		bool found = false;
>   		int num_res;
> @@ -571,22 +571,24 @@ static int hisi_lpc_acpi_probe(struct device *hostdev)
>   
>   		ret = platform_device_add_resources(pdev, res, num_res);
>   		if (ret)
> -			goto fail;
> +			goto fail_put_device;
>   
>   		ret = platform_device_add_data(pdev, cell->pdata,
>   					       cell->pdata_size);
>   		if (ret)
> -			goto fail;
> +			goto fail_put_device;
>   
>   		ret = platform_device_add(pdev);
>   		if (ret)
> -			goto fail;
> +			goto fail_put_device;
>   
>   		acpi_device_set_enumerated(child);
>   	}
>   
>   	return 0;
>   
> +fail_put_device:
> +	platform_device_put(pdev);

is this enough? As I see, this invokes platform_device_release(), but we 
would still need platform_device_del() to drop the pdev resources. 
hisi_lpc_acpi_remove_subdev() calls platform_device_unregister(), so it 
seems proper to do that here also. Please check it.

Thanks,
John

>   fail:
>   	hisi_lpc_acpi_remove(hostdev);
>   	return ret;