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@xxxxxxxxx]
Sent: 2017å¹´11æ??14æ?¥ 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 ------
>> Â drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 5 -----
>> Â 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)
>> Â {
>> Â Â Â Â Â struct amdgpu_gtt_mgr *mgr = man->priv;
>> Â -Â Â Â spin_lock(&mgr->lock);
>> -Â Â Â if (!drm_mm_clean(&mgr->mm)) {
>> -Â Â Â Â Â Â Â spin_unlock(&mgr->lock);
>> -Â Â Â Â Â Â Â return -EBUSY;
>> -Â Â Â }
>> -
>> Â Â Â Â Â drm_mm_takedown(&mgr->mm);
>> Â Â Â Â Â spin_unlock(&mgr->lock);
>> Â Â Â Â Â 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)
>> Â Â Â Â Â struct amdgpu_vram_mgr *mgr = man->priv;
>> Â Â Â Â Â Â spin_lock(&mgr->lock);
>> -Â Â Â if (!drm_mm_clean(&mgr->mm)) {
>> -Â Â Â Â Â Â Â spin_unlock(&mgr->lock);
>> -Â Â Â Â Â Â Â return -EBUSY;
>> -Â Â Â }
>> -
>> Â Â Â Â Â drm_mm_takedown(&mgr->mm);
>> Â Â Â Â Â spin_unlock(&mgr->lock);
>> Â Â Â Â Â kfree(mgr);
>
>
