linux-kernel - Re: [PATCH RESEND] drm/amd/display: Initialize return value in dm_cache

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] [day] [month] [year] [list]

Message-ID: <ca29530d-f890-47b5-b254-20c4ef301f7d@gmail.com>
Date: Thu, 9 Oct 2025 01:00:16 +0300
From: Eslam Khafagy <eslam.medhat1993@...il.com>
To: Mario Limonciello <mario.limonciello@....com>,
 Harry Wentland <harry.wentland@....com>, Leo Li <sunpeng.li@....com>,
 Rodrigo Siqueira <siqueira@...lia.com>,
 Alex Deucher <alexander.deucher@....com>,
 Christian König <christian.koenig@....com>,
 David Airlie <airlied@...il.com>, Simona Vetter <simona@...ll.ch>,
 Alex Hung <alex.hung@....com>, Wayne Lin <Wayne.Lin@....com>,
 Aurabindo Pillai <aurabindo.pillai@....com>,
 Tom Chung <chiahsuan.chung@....com>,
 Dominik Kaszewski <dominik.kaszewski@....com>,
 Yilin Chen <Yilin.Chen@....com>,
 "open list:AMD DISPLAY CORE" <amd-gfx@...ts.freedesktop.org>,
 "open list:DRM DRIVERS" <dri-devel@...ts.freedesktop.org>,
 open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RESEND] drm/amd/display: Initialize return value in
 dm_cache_state()


On 10/8/25 05:15, Mario Limonciello wrote:
>
>
> On 10/7/2025 5:45 PM, Eslam Khafagy wrote:
>> Initialize the return variable "r" to 0 in dm_cache_state() to fix
>> a potential use of uninitialized variable warning.
>>
>> The return value for this function might not be a PTR_ERR, in casse if
>> condition fails. In that case we ensure predictable reutrn.
>
> Can you walk me through your thought process?  I looked at all 
> possible returns for drm_atomic_helper_suspend() and they all return 
> ERR_PTR() or a state.
>
> So I don't see how the IS_ERR() clause could have a problem.
Hello ,

Thank you for the response. Initially i was working on warnings via 
coverity scan.
Initially my thinking was just by following the sequence of 
dm_cache_state you can see that there was a potential issue if
drm_atomic_helper_suspend returned a non valid pointer that is not PTR_ERR.

But having a second look after your response, indeed it shouldn't be the 
case. so please feel free to drop this patch.

>>
>> Signed-off-by: Eslam Khafagy <eslam.medhat1993@...il.com>
>> ---
>>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> 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 8e1622bf7a42..6b4f3eb9ce48 100644
>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>> @@ -3115,7 +3115,7 @@ static void hpd_rx_irq_work_suspend(struct 
>> amdgpu_display_manager *dm)
>>     static int dm_cache_state(struct amdgpu_device *adev)
>>   {
>> -    int r;
>> +    int r = 0;
>>         adev->dm.cached_state = 
>> drm_atomic_helper_suspend(adev_to_drm(adev));
>>       if (IS_ERR(adev->dm.cached_state)) {
>