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From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
Date: Thu, 15 Feb 2024 14:31:09 +0200 (EET)
To: Armin Wolf <W_Armin@gmx.de>
cc: corentin.chary@gmail.com, luke@ljones.dev, 
    Hans de Goede <hdegoede@redhat.com>, platform-driver-x86@vger.kernel.org, 
    LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/5] platform/x86: wmi: Check if event data is not NULL
In-Reply-To: <20240214070433.2677-3-W_Armin@gmx.de>
Message-ID: <e03b600e-6ad2-1dd1-c4af-56ebfce51f12@linux.intel.com>
References: <20240214070433.2677-1-W_Armin@gmx.de> <20240214070433.2677-3-W_Armin@gmx.de>
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On Wed, 14 Feb 2024, Armin Wolf wrote:

> WMI event drivers which do not have no_notify_data set expect
> that each WMI event contains valid data. Evaluating _WED however
> might return no data, which can cause issues with such drivers.
> 
> Fix this by validating that evaluating _WED did return data.
> 
> Signed-off-by: Armin Wolf <W_Armin@gmx.de>
> ---
>  drivers/platform/x86/wmi.c | 11 +++++++++--
>  1 file changed, 9 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
> index 34d8f55afaad..8a916887c546 100644
> --- a/drivers/platform/x86/wmi.c
> +++ b/drivers/platform/x86/wmi.c
> @@ -1211,6 +1211,7 @@ static void wmi_notify_driver(struct wmi_block *wblock)
>  {
>  	struct wmi_driver *driver = drv_to_wdrv(wblock->dev.dev.driver);
>  	struct acpi_buffer data = { ACPI_ALLOCATE_BUFFER, NULL };
> +	union acpi_object *obj = NULL;
>  	acpi_status status;
> 
>  	if (!driver->no_notify_data) {
> @@ -1219,12 +1220,18 @@ static void wmi_notify_driver(struct wmi_block *wblock)
>  			dev_warn(&wblock->dev.dev, "Failed to get event data\n");
>  			return;
>  		}
> +
> +		obj = data.pointer;
> +		if (!obj) {
> +			dev_warn(&wblock->dev.dev, "Event contains not event data\n");
> +			return;
> +		}
>  	}
> 
>  	if (driver->notify)
> -		driver->notify(&wblock->dev, data.pointer);
> +		driver->notify(&wblock->dev, obj);
> 
> -	kfree(data.pointer);
> +	kfree(obj);

Hi Armin,

While looking into this patch, I failed to connect the mention of 
no_notify_data in the commit message with the code change that does
nothing differently based no_notify_data being set or not, AFAICT.

It could be just that you need to explain things better in the commit 
message, I'm not sure.

-- 
 i.