Re: [PATCH 01/10] drm/ttm: allocate resource object instead of embedding it v2

["Christian König" <ckoenig.leichtzumerken@gmail.com>]

Am 08.06.21 um 07:29 schrieb Thomas Hellström (Intel):
> Hi,
>
> On 6/7/21 7:59 PM, Christian König wrote:
>>
>>
>> Am 07.06.21 um 19:58 schrieb Thomas Hellström (Intel):
>>>
>>> On 6/7/21 7:54 PM, Christian König wrote:
>>>>
>>>>
>>>> Am 07.06.21 um 19:06 schrieb Thomas Hellström (Intel):
>>>>>
>>>>> On 6/7/21 6:40 PM, Thomas Hellström (Intel) wrote:
>>>>>>
>>>>>> On 6/2/21 12:09 PM, Christian König wrote:
>>>>>> ...
>>>>>>> @@ -728,14 +728,15 @@ static int ttm_bo_add_move_fence(struct 
>>>>>>> ttm_buffer_object *bo,
>>>>>>>    */
>>>>>>>   static int ttm_bo_mem_force_space(struct ttm_buffer_object *bo,
>>>>>>>                     const struct ttm_place *place,
>>>>>>> -                  struct ttm_resource *mem,
>>>>>>> +                  struct ttm_resource **mem,
>>>>>>>                     struct ttm_operation_ctx *ctx)
>>>>>>>   {
>>>>>>>       struct ttm_device *bdev = bo->bdev;
>>>>>>> -    struct ttm_resource_manager *man = ttm_manager_type(bdev, 
>>>>>>> mem->mem_type);
>>>>>>> +    struct ttm_resource_manager *man;
>>>>>>>       struct ww_acquire_ctx *ticket;
>>>>>>>       int ret;
>>>>>>>   +    man = ttm_manager_type(bdev, (*mem)->mem_type);
>>>>>>
>>>>>> Isn't (*mem) uninitialized here? Should be place->mem_type? 
>>>>>> Eviction is immediately sent to the bushes.
>>>>>>
>>>>>> Got at least one additional NULL pointer deref to track down in 
>>>>>> the eviction code, but could be a merge error of mine as well.
>>>>>
>>>>> Actually this last one was probably due to a bad temporary fix of 
>>>>> the above one.
>>>>
>>>> I've found one more warning during my testing now. But that is just 
>>>> a false positive.
>>>>
>>>> Apart from that I haven't seen any other fallout, but fingers crossed.
>>>
>>> vmwgfx doesn't seem to happy. It works AFAICT., but warns in 
>>> vmw_move() about ttm_bo_assign_mem() replacing an existing resource.
>>
>> Yeah, that's the one I've just fixed. Patch is underway.
>
> If that's the move_to_ghost patch, I don't think that would fix the 
> vmwgfx issue, as IIRC vmwgfx ever uses ghost objects.

Mhm, could be that vmwgfx is hitting the same warning with a different 
backtrace.

Do you have the log to double check?

Thanks,
Christian.

>
> /Thomas
>
>