[PATCH 05/10] drm/amdgpu:fix memleak in takedown

[Christian König]

Makes sense, Reviewed-by: Christian König <christian.koenig at amd.com> fro 
this one as well.

Regards,
Christian.

Am 14.11.2017 um 16:00 schrieb Liu, Monk:
> Actually " drm_mm_takedown" below will give you the warning if some BO is still in MM
> That means below part is totally useless:
>
>>>    -    spin_lock(&mgr->lock);
>>> -    if (!drm_mm_clean(&mgr->mm)) {
>>> -        spin_unlock(&mgr->lock);
>>> -        return -EBUSY;
>>> -    }
>>> -
> And the worse thing is this "return -EBUSY" would lead to memory leak because it blocks following kfree() on mgr...
> BR Monk
>
> -----Original Message-----
> From: Christian König [mailto:ckoenig.leichtzumerken at gmail.com]
> Sent: 2017年11月14日 20:01
> To: Liu, Monk <Monk.Liu at amd.com>; amd-gfx at lists.freedesktop.org
> Subject: Re: [PATCH 05/10] drm/amdgpu:fix memleak in takedown
>
> Am 14.11.2017 um 12:52 schrieb Christian König:
>> Am 14.11.2017 um 10:07 schrieb Monk Liu:
>>> this can fix the memory leak under the case that not all BO are freed
>>> during "takedown" stage, because originally it blocks following kfree
>>> on mgr.
>> NAK, all BOs must be freed before we take down at least the GTT manager.
> Ah, wait a second. That is the address space manager here!
>
> Mhm, returning -EBUSY is probably not a good idea, but we should at least print some warning.
>
> Regards,
> Christian.
>
>> That we run into a memory leak is intended, cause that is still better
>> than crashing the system because we access already freed up memory.
>>
>> Regards,
>> Christian.
>>
>>> Change-Id: I56e832ac317215a4d9f58edb8e75ea722158715c
>>> Signed-off-by: Monk Liu <Monk.Liu at amd.com>
>>> ---
>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c  | 6 ------
>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 5 -----
>>>    2 files changed, 11 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c
>>> index 88709f9..72819cc 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gtt_mgr.c
>>> @@ -76,12 +76,6 @@ static int amdgpu_gtt_mgr_fini(struct
>>> ttm_mem_type_manager *man)
>>>    {
>>>        struct amdgpu_gtt_mgr *mgr = man->priv;
>>>    -    spin_lock(&mgr->lock);
>>> -    if (!drm_mm_clean(&mgr->mm)) {
>>> -        spin_unlock(&mgr->lock);
>>> -        return -EBUSY;
>>> -    }
>>> -
>>>        drm_mm_takedown(&mgr->mm);
>>>        spin_unlock(&mgr->lock);
>>>        kfree(mgr);
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
>>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
>>> index 4ca622b..3e883e5 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
>>> @@ -68,11 +68,6 @@ static int amdgpu_vram_mgr_fini(struct
>>> ttm_mem_type_manager *man)
>>>        struct amdgpu_vram_mgr *mgr = man->priv;
>>>          spin_lock(&mgr->lock);
>>> -    if (!drm_mm_clean(&mgr->mm)) {
>>> -        spin_unlock(&mgr->lock);
>>> -        return -EBUSY;
>>> -    }
>>> -
>>>        drm_mm_takedown(&mgr->mm);
>>>        spin_unlock(&mgr->lock);
>>>        kfree(mgr);
>>