Re: [PATCH v11 01/10] drm/ttm/tests: Fix a warning in ttm_bo_unreserve_bulk

[Karolina Stolarek <karolina.stolarek@intel.com>]

On 18.04.2024 10:15, Christian König wrote:
> Am 17.04.24 um 15:03 schrieb Karolina Stolarek:
>> BOs in a bulk move have to share the same reservation object. That is
>> not the case in the ttm_bo_unreserve_bulk subtest. Share bo2's resv
>> object with bo1 to fix the issue.
>>
>> Fixes: 995279d280d1 ("drm/ttm/tests: Add tests for ttm_bo functions")
>> Signed-off-by: Karolina Stolarek <karolina.stolarek@intel.com>
>> ---
>>   drivers/gpu/drm/ttm/tests/ttm_bo_test.c | 3 +++
>>   1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/ttm/tests/ttm_bo_test.c 
>> b/drivers/gpu/drm/ttm/tests/ttm_bo_test.c
>> index 1f8a4f8adc92..632306adc4a1 100644
>> --- a/drivers/gpu/drm/ttm/tests/ttm_bo_test.c
>> +++ b/drivers/gpu/drm/ttm/tests/ttm_bo_test.c
>> @@ -339,6 +339,9 @@ static void ttm_bo_unreserve_bulk(struct kunit *test)
>>       bo1 = ttm_bo_kunit_init(test, test->priv, BO_SIZE);
>>       bo2 = ttm_bo_kunit_init(test, test->priv, BO_SIZE);
>> +    /* Share the reservation object in the same bulk move */
>> +    bo1->base.resv = bo2->base.resv;
>> +
> 
> In a real world driver that would be illegal because it is racy for the 
> UAPI. It might work in the test case, but it could leak any fence 
> storage allocate for the bo1 reservation object.
> 
> We should probably avoid that and I would rather modify 
> ttm_bo_kunit_init() so that it gets the reservation object which should 
> be used for the newly created BO with the default behavior if the 
> parameter is NULL.

Thanks for providing the context, makes sense. I'll extend that helper.

All the best,
Karolina