From: "Arnd Bergmann" <arnd@arndb.de>
To: "Dmitry Baryshkov" <dmitry.baryshkov@oss.qualcomm.com>,
"Arnd Bergmann" <arnd@kernel.org>
Cc: "Rob Clark" <robin.clark@oss.qualcomm.com>,
"Dmitry Baryshkov" <lumag@kernel.org>,
"Dave Airlie" <airlied@gmail.com>,
"Simona Vetter" <simona@ffwll.ch>,
"Nathan Chancellor" <nathan@kernel.org>,
"Abhinav Kumar" <quic_abhinavk@quicinc.com>,
"Abhinav Kumar" <abhinav.kumar@linux.dev>,
"Jessica Zhang" <jessica.zhang@oss.qualcomm.com>,
"Sean Paul" <sean@poorly.run>,
"Marijn Suijten" <marijn.suijten@somainline.org>,
"Nick Desaulniers" <nick.desaulniers+lkml@gmail.com>,
"Bill Wendling" <morbo@google.com>,
"Justin Stitt" <justinstitt@google.com>,
"Antonino Maniscalco" <antomani103@gmail.com>,
"Konrad Dybcio" <konrad.dybcio@oss.qualcomm.com>,
"Jun Nie" <jun.nie@linaro.org>,
linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org,
freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org,
llvm@lists.linux.dev
Subject: Re: [PATCH] drm/msm/dpu: avoid uninitialized variable use
Date: Thu, 07 Aug 2025 17:08:31 +0200 [thread overview]
Message-ID: <76680ece-f88c-4960-a263-b96f64c35bbf@app.fastmail.com> (raw)
In-Reply-To: <ouan6tfmoefwuvs7wmhpzjdwmxfhqh3ad26j5tmwdugnq7ieda@ddw6dfqtq27g>
On Thu, Aug 7, 2025, at 10:09, Dmitry Baryshkov wrote:
> On Thu, Aug 07, 2025 at 09:19:48AM +0200, Arnd Bergmann wrote:
>>
>> The bug is real, but the suggestion from clang to set it to NULL is
>> unfortunately just as harmful as dereferencing a NULL pointer is little
>> better than uninitialized data.
>
>
> Having no plane->crtc is a valid setting and it is handled inside
> drm_atomic_helper_check_plane_state() by setting plane_state->visible =
> false and returning early. Setting crtc_state to NULL is a correct fix.
> Could you please send it?
Ah, I see. I saw the crtc_state dereference in
WARN_ON(plane_state->crtc && plane_state->crtc != crtc_state->crtc);
but that is indeed guarded by the plane_state->crtc check.
Nathan's patch is sufficient then.
Arnd
prev parent reply other threads:[~2025-08-07 15:08 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-08-07 7:19 [PATCH] drm/msm/dpu: avoid uninitialized variable use Arnd Bergmann
2025-08-07 8:09 ` Dmitry Baryshkov
2025-08-07 14:34 ` Nathan Chancellor
2025-08-09 8:20 ` Dmitry Baryshkov
2025-08-10 0:20 ` Nathan Chancellor
2025-08-07 15:08 ` Arnd Bergmann [this message]
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