[PATCH] drm/ttm: fix leaking fences via ttm_buffer_object_transfer

[Christian König]

Am 25.02.20 um 20:11 schrieb Alex Deucher:
> On Tue, Feb 25, 2020 at 2:09 PM Christian König
> <ckoenig.leichtzumerken at gmail.com> wrote:
>> Am 25.02.20 um 19:56 schrieb Alex Deucher:
>>> From: Ahzo <Ahzo at tutanota.com>
>>>
>>> Set the drm_device to NULL, so that the newly created buffer object
>>> doesn't appear to use the embedded gem object.
>>>
>>> This is necessary, because otherwise no corresponding dma_resv_fini for
>>> the dma_resv_init is called, resulting in a memory leak.
>>>
>>> The dma_resv_fini in ttm_bo_release_list is only called if the embedded
>>> gem object is not used, which is determined by checking if the
>>> drm_device is NULL.
>>>
>>> Bug: https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgitlab.freedesktop.org%2Fdrm%2Famd%2Fissues%2F958&data=02%7C01%7Cchristian.koenig%40amd.com%7Caa3f774da03e4dfcc09a08d7ba268305%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637182546879144030&sdata=N8WxYZZRj5obMU5SLv0giog0a1sCYi%2FouxSuWNom0gw%3D&reserved=0
>>> Fixes: 1e053b10ba60 ("drm/ttm: use gem reservation object")
>>> Signed-off-by: Ahzo <Ahzo at tutanota.com>
>>> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
>> Good catch I was trying to hunt that one down as well.
>>
>> Reviewed-by: Christian König <christian.koenig at amd.com>
> Can you apply it to drm-misc?

Sure, but not today. Need to get the kids to bed.

Christian.

>
> Thanks,
>
> Alex
>
>>> ---
>>>    drivers/gpu/drm/ttm/ttm_bo_util.c | 1 +
>>>    1 file changed, 1 insertion(+)
>>>
>>> diff --git a/drivers/gpu/drm/ttm/ttm_bo_util.c b/drivers/gpu/drm/ttm/ttm_bo_util.c
>>> index c8e359ded1df..44c1e7adfb7c 100644
>>> --- a/drivers/gpu/drm/ttm/ttm_bo_util.c
>>> +++ b/drivers/gpu/drm/ttm/ttm_bo_util.c
>>> @@ -514,6 +514,7 @@ static int ttm_buffer_object_transfer(struct ttm_buffer_object *bo,
>>>                fbo->base.base.resv = &fbo->base.base._resv;
>>>
>>>        dma_resv_init(&fbo->base.base._resv);
>>> +     fbo->base.base.dev = NULL;
>>>        ret = dma_resv_trylock(&fbo->base.base._resv);
>>>        WARN_ON(!ret);
>>>