linux-kernel - Re: [PATCH v2] platform/x86/dell/dell-rbtn: Fix resources leaking on error path

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Message-ID: <066c16a1-265f-e3f9-a8c9-25115aad9451@redhat.com>
Date:   Tue, 13 Jun 2023 12:41:54 +0200
From:   Hans de Goede <hdegoede@...hat.com>
To:     Michal Wilczynski <michal.wilczynski@...el.com>,
        linux-acpi@...r.kernel.org
Cc:     rafael@...nel.org, andriy.shevchenko@...el.com,
        ilpo.jarvinen@...ux.intel.com, pali@...nel.org,
        markgross@...nel.org, fengguang.wu@...el.com,
        dvhart@...ux.intel.com, platform-driver-x86@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Subject: Re: [PATCH v2] platform/x86/dell/dell-rbtn: Fix resources leaking on
 error path

Hi,

On 6/13/23 10:43, Michal Wilczynski wrote:
> Currently rbtn_add() in case of failure is leaking resources. Fix this
> by adding a proper rollback. Move devm_kzalloc() before rbtn_acquire(),
> so it doesn't require rollback in case of failure. While at it, remove
> unnecessary assignment of NULL to device->driver_data and unnecessary
> whitespace, plus add a break for the default case in a switch.
> 
> Suggested-by: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
> Fixes: 817a5cdb40c8 ("dell-rbtn: Dell Airplane Mode Switch driver")
> Signed-off-by: Michal Wilczynski <michal.wilczynski@...el.com>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> Acked-by: Rafael J. Wysocki <rafael@...nel.org>
> ---
> v2:
>  - move devm_kzalloc before rbtn_acquire as suggested


Thank you for your patch, I've applied this patch to my review-hans 
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.

Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.

Regards,

Hans




>  drivers/platform/x86/dell/dell-rbtn.c | 13 +++++++------
>  1 file changed, 7 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/platform/x86/dell/dell-rbtn.c b/drivers/platform/x86/dell/dell-rbtn.c
> index aa0e6c907494..c8fcb537fd65 100644
> --- a/drivers/platform/x86/dell/dell-rbtn.c
> +++ b/drivers/platform/x86/dell/dell-rbtn.c
> @@ -395,16 +395,16 @@ static int rbtn_add(struct acpi_device *device)
>  		return -EINVAL;
>  	}
>  
> +	rbtn_data = devm_kzalloc(&device->dev, sizeof(*rbtn_data), GFP_KERNEL);
> +	if (!rbtn_data)
> +		return -ENOMEM;
> +
>  	ret = rbtn_acquire(device, true);
>  	if (ret < 0) {
>  		dev_err(&device->dev, "Cannot enable device\n");
>  		return ret;
>  	}
>  
> -	rbtn_data = devm_kzalloc(&device->dev, sizeof(*rbtn_data), GFP_KERNEL);
> -	if (!rbtn_data)
> -		return -ENOMEM;
> -
>  	rbtn_data->type = type;
>  	device->driver_data = rbtn_data;
>  
> @@ -420,10 +420,12 @@ static int rbtn_add(struct acpi_device *device)
>  		break;
>  	default:
>  		ret = -EINVAL;
> +		break;
>  	}
> +	if (ret)
> +		rbtn_acquire(device, false);
>  
>  	return ret;
> -
>  }
>  
>  static void rbtn_remove(struct acpi_device *device)
> @@ -442,7 +444,6 @@ static void rbtn_remove(struct acpi_device *device)
>  	}
>  
>  	rbtn_acquire(device, false);
> -	device->driver_data = NULL;
>  }
>  
>  static void rbtn_notify(struct acpi_device *device, u32 event)