Re: [PATCH 2/5] platform/x86: wmi: Check if event data is not NULL

[Armin Wolf <W_Armin@gmx.de>]

Am 15.02.24 um 13:31 schrieb Ilpo Järvinen:

> 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.

Here the _WED ACPI control method is only evaluated if driver->no_notify_data is not set.
So the returned ACPI object should only be validated in this case, as we pass NULL otherwise.

Armin Wolf