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Date:   Mon, 21 Feb 2022 08:06:15 +0100
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Subject: Re: [PATCH] drm/amdgpu: Initialize value of r in amdgpu_fill_buffer()
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To:     Souptick Joarder <jrdr.linux@gmail.com>, alexander.deucher@amd.com,
        Xinhui.Pan@amd.com, airlied@linux.ie, daniel@ffwll.ch,
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References: <20220218185312.34464-1-jrdr.linux@gmail.com>
From:   =?UTF-8?Q?Christian_K=c3=b6nig?= <christian.koenig@amd.com>
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Am 18.02.22 um 19:53 schrieb Souptick Joarder:
> From: "Souptick Joarder (HPE)" <jrdr.linux@gmail.com>
>
> Kernel test robot reported warning ->
> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c:2129:2: warning: Undefined
> or garbage value returned to caller [clang-analyzer-core.
> uninitialized.UndefReturn]

Good catch, but that fix is usually seen as bad practice.

The warning is a false positive because the code path which would lead 
to returning an undefined value can never happen. There is just no way 
the compiler could know that.

I suggest to better initialize the return value directly before the 
error handling to indicate that when we have reached this point we can 
return success safely.

Regards,
Christian.

>
> Initialize r inside amdgpu_fill_buffer().
>
> Reported-by: kernel test robot <lkp@intel.com>
> Signed-off-by: Souptick Joarder (HPE) <jrdr.linux@gmail.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> index 414a22dddc78..5fafb223177f 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
> @@ -2089,7 +2089,7 @@ int amdgpu_fill_buffer(struct amdgpu_bo *bo,
>   	struct amdgpu_ring *ring = adev->mman.buffer_funcs_ring;
>   	struct dma_fence *fence = NULL;
>   	struct amdgpu_res_cursor dst;
> -	int r;
> +	int r = 0;
>   
>   	if (!adev->mman.buffer_funcs_enabled) {
>   		DRM_ERROR("Trying to clear memory with ring turned off.\n");