linux-kernel - Re: [PATCH] drm/amdgpu: Initialize variable before use

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Message-ID: <CADnq5_MapuHn=yNSkYf6yUzatXps2sMJPNLJ-wUad5jqg+GuQw@mail.gmail.com>
Date:   Wed, 2 Oct 2019 09:41:21 -0400
From:   Alex Deucher <alexdeucher@...il.com>
To:     "Siqueira, Rodrigo" <Rodrigo.Siqueira@....com>
Cc:     "amd-gfx@...ts.freedesktop.org" <amd-gfx@...ts.freedesktop.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Zhou, David(ChunMing)" <David1.Zhou@....com>,
        "Li, Sun peng (Leo)" <Sunpeng.Li@....com>,
        "Kazlauskas, Nicholas" <Nicholas.Kazlauskas@....com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        "Deucher, Alexander" <Alexander.Deucher@....com>,
        "Wentland, Harry" <Harry.Wentland@....com>,
        "Koenig, Christian" <Christian.Koenig@....com>
Subject: Re: [PATCH] drm/amdgpu: Initialize variable before use

On Mon, Sep 30, 2019 at 4:09 PM Siqueira, Rodrigo
<Rodrigo.Siqueira@....com> wrote:
>
> The 'debug_data' variable gets printed in debug statements without a
> prior initialization in the function
> hubbub1_verify_allow_pstate_change_high, as reported when building with
> gcc 9.1.0:
>
> warning: ‘debug_data’ may be used uninitialized in this function [-Wmaybe-uninitialized]
>   290 |  printk##once(KERN_##level "[" DRM_NAME "] " fmt, ##__VA_ARGS__)
>       |  ^~~~~~
> dc/dcn10/dcn10_hubbub.c:134:15: note: ‘debug_data’ was declared here
>   134 |  unsigned int debug_data;
>
> Note that initialize debug_data with 0, in this case, is safe because we
> have a loop in a few lines below that will initialize this variable with
> the proper value.
>
> Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@....com>

Reviewed-by: Alex Deucher <alexander.deucher@....com>

> ---
>  drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hubbub.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hubbub.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hubbub.c
> index a780057e2dbc..b6967a7e6c7b 100644
> --- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hubbub.c
> +++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hubbub.c
> @@ -133,7 +133,7 @@ bool hubbub1_verify_allow_pstate_change_high(
>         static unsigned int max_sampled_pstate_wait_us; /* data collection */
>         static bool forced_pstate_allow; /* help with revert wa */
>
> -       unsigned int debug_data;
> +       unsigned int debug_data = 0;
>         unsigned int i;
>
>         if (forced_pstate_allow) {
> --
> 2.23.0
> _______________________________________________
> amd-gfx mailing list
> amd-gfx@...ts.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/amd-gfx

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