linux-kernel - Re: [PATCH v1 1/3] drm/admgpu: replace kmalloc() and memcpy() with kmemdup()

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Message-ID: <2a061534-7780-40a7-b058-98d1fc16915b@amd.com>
Date: Wed, 18 Dec 2024 13:33:40 +0530
From: "Lazar, Lijo" <lijo.lazar@....com>
To: Mirsad Todorovac <mtodorovac69@...il.com>,
 Alex Deucher <alexander.deucher@....com>,
 Victor Skvortsov <victor.skvortsov@....com>, amd-gfx@...ts.freedesktop.org,
 dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Cc: Christian König <christian.koenig@....com>,
 Xinhui Pan <Xinhui.Pan@....com>, David Airlie <airlied@...il.com>,
 Simona Vetter <simona@...ll.ch>, Zhigang Luo <Zhigang.Luo@....com>,
 Hawking Zhang <Hawking.Zhang@....com>, Yunxiang Li <Yunxiang.Li@....com>,
 Jack Xiao <Jack.Xiao@....com>, Vignesh Chander <Vignesh.Chander@....com>,
 Danijel Slivka <danijel.slivka@....com>
Subject: Re: [PATCH v1 1/3] drm/admgpu: replace kmalloc() and memcpy() with
 kmemdup()



On 12/18/2024 4:28 AM, Mirsad Todorovac wrote:
> The static analyser tool gave the following advice:
> 
> ./drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c:1266:7-14: WARNING opportunity for kmemdup
> 
>  → 1266         tmp = kmalloc(used_size, GFP_KERNEL);
>    1267         if (!tmp)
>    1268                 return -ENOMEM;
>    1269
>  → 1270         memcpy(tmp, &host_telemetry->body.error_count, used_size);
> 
> Replacing kmalloc() + memcpy() with kmemdump() doesn't change semantics.
> Original code works without fault, so this is not a bug fix but proposed improvement.
> 
> Link: https://lwn.net/Articles/198928/
> Fixes: 84a2947ecc85c ("drm/amdgpu: Implement virt req_ras_err_count")
> Cc: Alex Deucher <alexander.deucher@....com>
> Cc: "Christian König" <christian.koenig@....com>
> Cc: Xinhui Pan <Xinhui.Pan@....com>
> Cc: David Airlie <airlied@...il.com>
> Cc: Simona Vetter <simona@...ll.ch>
> Cc: Zhigang Luo <Zhigang.Luo@....com>
> Cc: Victor Skvortsov <victor.skvortsov@....com>
> Cc: Hawking Zhang <Hawking.Zhang@....com>
> Cc: Lijo Lazar <lijo.lazar@....com>
> Cc: Yunxiang Li <Yunxiang.Li@....com>
> Cc: Jack Xiao <Jack.Xiao@....com>
> Cc: Vignesh Chander <Vignesh.Chander@....com>
> Cc: Danijel Slivka <danijel.slivka@....com>
> Cc: amd-gfx@...ts.freedesktop.org
> Cc: dri-devel@...ts.freedesktop.org
> Cc: linux-kernel@...r.kernel.org
> Signed-off-by: Mirsad Todorovac <mtodorovac69@...il.com>

Reviewed-by: Lijo Lazar <lijo.lazar@....com>

Thanks,
Lijo

> ---
>  v1:
> 	initial version.
> 
>  drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> index c704e9803e11..0af469ec6fcc 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
> @@ -1263,12 +1263,10 @@ static int amdgpu_virt_cache_host_error_counts(struct amdgpu_device *adev,
>  	if (used_size > (AMD_SRIOV_RAS_TELEMETRY_SIZE_KB << 10))
>  		return 0;
>  
> -	tmp = kmalloc(used_size, GFP_KERNEL);
> +	tmp = kmemdup(&host_telemetry->body.error_count, used_size, GFP_KERNEL);
>  	if (!tmp)
>  		return -ENOMEM;
>  
> -	memcpy(tmp, &host_telemetry->body.error_count, used_size);
> -
>  	if (checksum != amd_sriov_msg_checksum(tmp, used_size, 0, 0))
>  		goto out;
>