linux-kernel - Re: [PATCH] amdgpu: fixes memleak issue when init failed

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Message-ID: <5c1510e2-9007-50b8-9be9-b8a00f943c9b@amd.com>
Date:   Tue, 21 Apr 2020 15:02:27 +0200
From:   Christian König <christian.koenig@....com>
To:     赵军奎 <bernard@...o.com>
Cc:     Alex Deucher <alexander.deucher@....com>,
        "David (ChunMing) Zhou" <David1.Zhou@....com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Tom St Denis <tom.stdenis@....com>,
        Ori Messinger <Ori.Messinger@....com>,
        Sam Ravnborg <sam@...nborg.org>, amd-gfx@...ts.freedesktop.org,
        dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
        opensource.kernel@...o.com
Subject: Re: [PATCH] amdgpu: fixes memleak issue when init failed

Am 21.04.20 um 14:09 schrieb 赵军奎:
> From: "Christian König" <christian.koenig@....com>
> Date: 2020-04-21 19:22:49
> To:  Bernard Zhao <bernard@...o.com>,Alex Deucher <alexander.deucher@....com>,"David (ChunMing) Zhou" <David1.Zhou@....com>,David Airlie <airlied@...ux.ie>,Daniel Vetter <daniel@...ll.ch>,Tom St Denis <tom.stdenis@....com>,Ori Messinger <Ori.Messinger@....com>,Sam Ravnborg <sam@...nborg.org>,amd-gfx@...ts.freedesktop.org,dri-devel@...ts.freedesktop.org,linux-kernel@...r.kernel.org
> Cc:  opensource.kernel@...o.com
> Subject: Re: [PATCH] amdgpu: fixes memleak issue when init failed>Am 21.04.20 um 13:17 schrieb Bernard Zhao:
>>> VRAM manager and DRM MM when init failed, there is no operaction
>>> to free kzalloc memory & remove device file.
>>> This will lead to memleak & cause stability issue.
>> NAK, failure to create sysfs nodes are not critical.
>>
>> Christian.
>>
> OK, get it.
> By the way, should i modify this patch to just handle <kfree(mgr)> in error branch, or that it is also unnecessary?

What you can do is to drop the "return ret" if anything with the sysfs 
nodes goes wrong and instead print the error code.

It's really annoying that loading, unloading and loading the driver 
again sometimes fails because we have a bug in the sysfs files cleanup.

We certainly should fix those bugs as well, but they are just not 
critical for correct driver functionality.

Regards,
Christian.

>
> Regards,
> Bernard
>
>>> Signed-off-by: Bernard Zhao <bernard@...o.com>
>>> ---
>>>    drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c | 24 ++++++++++++++++----
>>>    1 file changed, 19 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
>>> index 82a3299e53c0..4c5fb153e6b4 100644
>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vram_mgr.c
>>> @@ -175,30 +175,44 @@ static int amdgpu_vram_mgr_init(struct ttm_mem_type_manager *man,
>>>    	ret = device_create_file(adev->dev, &dev_attr_mem_info_vram_total);
>>>    	if (ret) {
>>>    		DRM_ERROR("Failed to create device file mem_info_vram_total\n");
>>> -		return ret;
>>> +		goto VRAM_TOTAL_FAIL;
>>>    	}
>>>    	ret = device_create_file(adev->dev, &dev_attr_mem_info_vis_vram_total);
>>>    	if (ret) {
>>>    		DRM_ERROR("Failed to create device file mem_info_vis_vram_total\n");
>>> -		return ret;
>>> +		goto VIS_VRAM_TOTA_FAIL;
>>>    	}
>>>    	ret = device_create_file(adev->dev, &dev_attr_mem_info_vram_used);
>>>    	if (ret) {
>>>    		DRM_ERROR("Failed to create device file mem_info_vram_used\n");
>>> -		return ret;
>>> +		goto VRAM_USED_FAIL;
>>>    	}
>>>    	ret = device_create_file(adev->dev, &dev_attr_mem_info_vis_vram_used);
>>>    	if (ret) {
>>>    		DRM_ERROR("Failed to create device file mem_info_vis_vram_used\n");
>>> -		return ret;
>>> +		goto VIS_VRAM_USED_FAIL;
>>>    	}
>>>    	ret = device_create_file(adev->dev, &dev_attr_mem_info_vram_vendor);
>>>    	if (ret) {
>>>    		DRM_ERROR("Failed to create device file mem_info_vram_vendor\n");
>>> -		return ret;
>>> +		goto VRAM_VERDOR_FAIL;
>>>    	}
>>>    
>>>    	return 0;
>>> +
>>> +VRAM_VERDOR_FAIL:
>>> +	device_remove_file(adev->dev, &dev_attr_mem_info_vis_vram_used);
>>> +VIS_VRAM_USED_FAIL:
>>> +	device_remove_file(adev->dev, &dev_attr_mem_info_vram_used);
>>> +RVAM_USED_FAIL:
>>> +	device_remove_file(adev->dev, &dev_attr_mem_info_vis_vram_total);
>>> +VIS_VRAM_TOTA_FAIL:
>>> +	device_remove_file(adev->dev, &dev_attr_mem_info_vram_total);
>>> +VRAM_TOTAL_FAIL:
>>> +	kfree(mgr);
>>> +	man->priv = NULL;
>>> +
>>> +	return ret;
>>>    }
>>>    
>>>    /**
>