[PATCH] drm/amdgpu: fix NULL pointer dereference when run App with DRI_PRIME=1

[Christian König]

Am 25.05.2018 um 11:51 schrieb Zhang, Jerry (Junwei):
> On 05/25/2018 05:35 PM, Christian König wrote:
>> Am 25.05.2018 um 10:23 schrieb Zhang, Jerry (Junwei):
>>> On 05/25/2018 03:54 PM, Christian König wrote:
>>>> Am 25.05.2018 um 09:20 schrieb Zhang, Jerry (Junwei):
>>>>> On 05/25/2018 02:44 PM, Christian König wrote:
>>>>>> NAK, that probably just fixed the symptom but not the underlying 
>>>>>> problem.
>>>>>>
>>>>>> Somebody is accessing the page array when it should never be 
>>>>>> accessed.
>>>>>
>>>>> If prime import as GTT bo by default(now it's CPU bo), it would 
>>>>> happens
>>>>> quickly when GTT sg bo creation rather than next cs validation.
>>>>>
>>>>> Since ttm_sg_tt_init() only allocates gtt->ttm.dma_address if sg 
>>>>> bo is
>>>>> created, it would fail to access ttm->pages when ttm populate.
>>>>
>>>> And exactly that's the problem, and imported BO should never populate.
>>>>
>>>>>
>>>>> current error happens in ttm populate from cs validation, the sg 
>>>>> bo is
>>>>> imported from exporter.
>>>>>
>>>>>>
>>>>>> How did you manage to trigger this?
>>>>>
>>>>> PRI_PRIME=1 with Unigine heaven.
>>>>
>>>> Going to give that a try, but the last time I check that worked as 
>>>> expected.
>>>
>>> FYI.
>>> PRI_PRIME=1 glxinfo will not trigger that, but the game does.
>>
>> Just tested and it works perfectly fine.
>>
>> Is that on the closed stack or the open stack?
>
> I used unified driver(latest 18.20 build) + drm-next kernel, installed 
> as all open stack on A+A platform.
> (issue was found by 18.20 build, all open stack(dkms driver))
>
> BTW, How did you get the UMD? apt-get or build by yourself?

That's self build Mesa+libdrm.

Do you have the apt url and/or package versions at hand you used for the 
test?

Christian.

>
>
> Jerry