From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C0C0B21FF38; Thu, 7 Aug 2025 07:20:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754551223; cv=none; b=m1/TRd9q2mgI24v2OteeVO+S93/9Ep1cptXW7U+fyVJOX8xeye4tlSLYZgPMM4sQ3VNiL35CuzdyYkumixMaKGcSV+l1wijp1zwVa5M78M+zgnTKgP+GIp8E1FVB2+6Spghg1HibQYpjI4oJ4awwHfy73aCb6vBugomTbWVTQyg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754551223; c=relaxed/simple; bh=QAymJJ06cre5xL6TD3wl31zS7/sMx5/eUajrkA/4UAI=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=P58t5Q4CYDkH7F4mC2AsKEgwIXWPbYvdjk/qB/gksuzwCQm6GTrg+qBnqaubZD3F6gwF8UuNHRrr7oDzdWi/in8+/8s8sT9QcoXS3MxJcZD+15X1HkqMer3vYLzMaI9oCKymHhrn+tVuWCUpbRskjhoZq7tI8hHHez4SaefzZbs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=pJce7DAc; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="pJce7DAc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D271C4CEEB; Thu, 7 Aug 2025 07:20:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754551223; bh=QAymJJ06cre5xL6TD3wl31zS7/sMx5/eUajrkA/4UAI=; h=From:To:Cc:Subject:Date:From; b=pJce7DAc80rSzLxSCt141wdl8kSmtmRpLIv3RS4HCQ8+tcgchWjbo/HJh/RU9sa2u n1ZFXW8UNUGbTVpZpfmXhaNSioyP8FziwRp9aeCvYVq4dCdx+eBBN6sOKI8LuFvjR3 r7nqSC/NaRZFMR868vdH1UuVjqCCPmqogzUjrJ3XhPg3XlfIrEQu6HOhFQVRbqDt4C pwl2xDwy5bSf8L4oJCkZJaF4KFtJZejxc6IYOtSwc0sYmyXMSYljB0jK0TDcWAnKvp YwgtNpvdkcrJfVkJxINPQsMa0iTSHW7vvX3z+lw6iRxiY6PnLVrgI2+gXKHi/n5luH BCGxnY0daRUbA== From: Arnd Bergmann To: Rob Clark , Dmitry Baryshkov , David Airlie , Simona Vetter , Nathan Chancellor , Abhinav Kumar Cc: Arnd Bergmann , Abhinav Kumar , Jessica Zhang , Sean Paul , Marijn Suijten , Nick Desaulniers , Bill Wendling , Justin Stitt , Antonino Maniscalco , Konrad Dybcio , Jun Nie , 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: [PATCH] drm/msm/dpu: avoid uninitialized variable use Date: Thu, 7 Aug 2025 09:19:48 +0200 Message-Id: <20250807072016.4109051-1-arnd@kernel.org> X-Mailer: git-send-email 2.39.5 Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Arnd Bergmann clang-21 points out a variable that is conditionally initialized but then dereferenced: drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c:1138:6: error: variable 'crtc_state' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized] 1138 | if (plane_state->crtc) | ^~~~~~~~~~~~~~~~~ drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c:1142:58: note: uninitialized use occurs here 1142 | ret = dpu_plane_atomic_check_nosspp(plane, plane_state, crtc_state); | ^~~~~~~~~~ drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c:1138:2: note: remove the 'if' if its condition is always true 1138 | if (plane_state->crtc) | ^~~~~~~~~~~~~~~~~~~~~~ 1139 | crtc_state = drm_atomic_get_new_crtc_state(state, drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c:1132:35: note: initialize the variable 'crtc_state' to silence this warning 1132 | struct drm_crtc_state *crtc_state; | ^ | = NULL 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. Change the function to return an error in this case. Fixes: 774bcfb73176 ("drm/msm/dpu: add support for virtual planes") Signed-off-by: Arnd Bergmann --- drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c index 01171c535a27..4987f2f2fee0 100644 --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_plane.c @@ -1135,10 +1135,10 @@ static int dpu_plane_virtual_atomic_check(struct drm_plane *plane, if (IS_ERR(plane_state)) return PTR_ERR(plane_state); - if (plane_state->crtc) - crtc_state = drm_atomic_get_new_crtc_state(state, - plane_state->crtc); + if (!plane_state->crtc) + return -ENXIO; + crtc_state = drm_atomic_get_new_crtc_state(state, plane_state->crtc); ret = dpu_plane_atomic_check_nosspp(plane, plane_state, crtc_state); if (ret) return ret; -- 2.39.5