Re: [PATCH v6] drm/xe: Add a null pointer check

["Poosa, Karthik" <karthik.poosa@intel.com>]

On 25-03-2024 23:28, Matt Roper wrote:
> On Mon, Mar 25, 2024 at 07:42:23PM +0530, Karthik Poosa wrote:
>> Add a missing null pointer check.
> You have so many versions of this patch that I've lost track of which is
> which, but as I commented on an earlier version, this whole patch seems
> unnecessary.  All Intel devices will have at least one GT, and we can
> never "resume from runtime PM" before those GT(s) get initialized.  So a
> NULL return here is impossible.  If you want to be paranoid, you can add
> an assert to make that invariant clear and it will get compiled out of
> production releases.
>
>
> Matt
Unfortunately, I missed your comment on earlier version (v2). Will drop 
this patch.
>
>> v2: Release resources before returning error. (Riana)
>>
>> v3: Update commit message. (Badal)
>>
>> v4: Change drm_err to XE_WARN_ON. (Anshuman)
>>
>> v5: Fix XE_WARN_ON check. (Riana)
>>
>> v6: Update commit message. (Jani)
>>
>> Fixes: 09d88e3beb64 ("drm/xe/pm: Init pcode and restore vram on power lost")
>> Signed-off-by: Karthik Poosa <karthik.poosa@intel.com>
>> Reviewed-by: Riana Tauro <riana.tauro@intel.com>
>> ---
>>   drivers/gpu/drm/xe/xe_pm.c | 5 +++++
>>   1 file changed, 5 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
>> index cc650a92c2fc..f6837bd6f9a3 100644
>> --- a/drivers/gpu/drm/xe/xe_pm.c
>> +++ b/drivers/gpu/drm/xe/xe_pm.c
>> @@ -383,6 +383,11 @@ int xe_pm_runtime_resume(struct xe_device *xe)
>>   	 * really lost power. Detecting primary Gt power is sufficient.
>>   	 */
>>   	gt = xe_device_get_gt(xe, 0);
>> +	if (XE_WARN_ON(!gt)) {
>> +		err = -ENXIO;
>> +		goto out;
>> +	}
>> +
>>   	xe->d3cold.power_lost = xe_guc_in_reset(&gt->uc.guc);
>>   
>>   	if (xe->d3cold.allowed && xe->d3cold.power_lost) {
>> -- 
>> 2.25.1
>>