2024-02-15 12:31:31

by Ilpo Järvinen

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

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 <[email protected]>
> ---
> 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.



2024-02-15 20:28:00

by Armin Wolf

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

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 <[email protected]>
>> ---
>> 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


2024-02-19 11:57:21

by Ilpo Järvinen

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

On Thu, 15 Feb 2024, Armin Wolf wrote:

> 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 <[email protected]>
> > > ---
> > > 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.

Yes, I'm sorry, it seems fine. For some reason I was very confused while
reviewing even if no_notify_data was mentioned right in the previous
context (maybe Iused some older version of the code while trying to figure
things out, I dunno).

--
i.