linux-kernel - Re: [PATCH v3] drm/amd/display: Fix exception handling in dm_validate_stream_and

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <5ebybqjohsoz7qhsenufkpkkw52w6tgikkbrzpegwotmefhnpn@m2cnzvsfai7v>
Date: Thu, 12 Jun 2025 11:08:10 -0300
From: Melissa Wen <mwen@...lia.com>
To: Markus Elfring <Markus.Elfring@....de>
Cc: amd-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org, 
	Alex Deucher <alexander.deucher@....com>, Alex Hung <alex.hung@....com>, 
	Aurabindo Pillai <aurabindo.pillai@....com>, Christian König <christian.koenig@....com>, 
	Daniel Vetter <daniel@...ll.ch>, David Airlie <airlied@...il.com>, 
	Dominik Kaszewski <dominik.kaszewski@....com>, Fangzhi Zuo <Jerry.Zuo@....com>, 
	Harry Wentland <harry.wentland@....com>, Leo Li <sunpeng.li@....com>, 
	Mario Limonciello <mario.limonciello@....com>, Roman Li <roman.li@....com>, Simona Vetter <simona@...ll.ch>, 
	Tom Chung <chiahsuan.chung@....com>, Wayne Lin <Wayne.Lin@....com>, 
	LKML <linux-kernel@...r.kernel.org>, kernel-janitors@...r.kernel.org, lkp@...el.com, 
	oe-kbuild-all@...ts.linux.dev, llvm@...ts.linux.dev, cocci@...ia.fr
Subject: Re: [PATCH v3] drm/amd/display: Fix exception handling in
 dm_validate_stream_and_context()

On 06/10, Markus Elfring wrote:
> From: Markus Elfring <elfring@...rs.sourceforge.net>
> Date: Tue, 10 Jun 2025 07:42:40 +0200
> 
> The label “cleanup” was used to jump to another pointer check despite of
> the detail in the implementation of the function “dm_validate_stream_and_context”
> that it was determined already that corresponding variables contained
> still null pointers.
> 
> 1. Thus return directly if
>    * a null pointer was passed for the function parameter “stream”
>      or
>    * a call of the function “dc_create_plane_state” failed.
> 
> 2. Use a more appropriate label instead.
> 
> 3. Delete two questionable checks.
> 
> 4. Omit extra initialisations (for the variables “dc_state” and “dc_plane_state”)
>    which became unnecessary with this refactoring.
> 
> 
> This issue was detected by using the Coccinelle software.
> 

Hi Markus,

Thanks for working on this improvement.
Overall, LGTM. Some nits below.

> Reported-by: kernel test robot <lkp@...el.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202506100312.Ms4XgAzW-lkp@intel.com/

As the patch wasn't merged yet, don't add these two kernel-bot-related lines.

You only need to add these lines "If you fix the issue in a separate
patch/commit (i.e. not just a new version of the same patch/commit)"

> Fixes: 5468c36d6285 ("drm/amd/display: Filter Invalid 420 Modes for HDMI TMDS")
> Signed-off-by: Markus Elfring <elfring@...rs.sourceforge.net>
> ---
> 
> V3:
> * Another function call was renamed.
> 
> * Recipient lists were adjusted once more.
> 
> V2:
> * The change suggestion was rebased on source files of
>   the software “Linux next-20250606”.
> 
> * Recipient lists were adjusted accordingly.
> 
> 
>  .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 20 ++++++++-----------
>  1 file changed, 8 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index 78816712afbb..7dc80b2fbd30 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -7473,19 +7473,19 @@ static enum dc_status dm_validate_stream_and_context(struct dc *dc,
>  						struct dc_stream_state *stream)
>  {
>  	enum dc_status dc_result = DC_ERROR_UNEXPECTED;
> -	struct dc_plane_state *dc_plane_state = NULL;
> -	struct dc_state *dc_state = NULL;
> +	struct dc_plane_state *dc_plane_state;
> +	struct dc_state *dc_state;
>  
>  	if (!stream)
> -		goto cleanup;
> +		return dc_result;
>  
>  	dc_plane_state = dc_create_plane_state(dc);
>  	if (!dc_plane_state)
> -		goto cleanup;
> +		return dc_result;
>  
>  	dc_state = dc_state_create(dc, NULL);
>  	if (!dc_state)
> -		goto cleanup;
> +		goto release_plane_state;
>  
>  	/* populate stream to plane */
>  	dc_plane_state->src_rect.height  = stream->src.height;
> @@ -7522,13 +7522,9 @@ static enum dc_status dm_validate_stream_and_context(struct dc *dc,
>  	if (dc_result == DC_OK)
>  		dc_result = dc_validate_global_state(dc, dc_state, DC_VALIDATE_MODE_ONLY);
>  
> -cleanup:
> -	if (dc_state)
> -		dc_state_release(dc_state);
> -
> -	if (dc_plane_state)
> -		dc_plane_state_release(dc_plane_state);
> -
> +	dc_state_release(dc_state);

For readability, I would add an extra line here...

> +release_plane_state:
> +	dc_plane_state_release(dc_plane_state);

and here.

With that, you can add my

Reviewed-by: Melissa Wen <mwen@...lia.com>

>  	return dc_result;
>  }
>  
> -- 
> 2.49.0
>