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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Sun, 21 Feb 2021 15:07:17 -0800
Message-ID: <CAHk-=wgiPxXzRNnfaXk7ozSWSu7fFU--kTmVjkDaTB05wwUk_g@mail.gmail.com>
Subject: Re: [git pull] drm for 5.12-rc1
To:     Dave Airlie <airlied@gmail.com>, Kevin Wang <kevin1.wang@amd.com>,
        Alex Deucher <alexander.deucher@amd.com>
Cc:     Daniel Vetter <daniel.vetter@ffwll.ch>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        LKML <linux-kernel@vger.kernel.org>
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On Thu, Feb 18, 2021 at 10:06 PM Dave Airlie <airlied@gmail.com> wrote:
>
> Let me know if there are any issues,

gcc was happy, and I obviously already pushed out my merge, but then
when I did my clang build afterwards, it reports:

  drivers/gpu/drm/amd/amdgpu/../pm/swsmu/smu_cmn.c:764:2: warning:
variable 'structure_size' is used uninitialized whenever switch
default is taken [-Wsometimes-uninitialized]
          default:
          ^~~~~~~
  drivers/gpu/drm/amd/amdgpu/../pm/swsmu/smu_cmn.c:770:23: note:
uninitialized use occurs here
          memset(header, 0xFF, structure_size);
                               ^~~~~~~~~~~~~~

and clang is very very right. That "default" case is completely
broken, and will generate a randomly sized memset. Not good.

Presumably that default case never happens, but if so it shouldn't exist.

Perhaps better yet, make the "default" case just do a "return" instead
of a break. Breaking out of the switch statement to code that cannot
possibly work is all kinds of mindless.

Kevin/Alex? This was introduced by commit de4b7cd8cb87
("drm/amd/pm/swsmu: unify the init soft gpu metrics function")

              Linus