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From:   Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
Cc:     harshit.m.mogalapalli@oracle.com, error27@gmail.com,
        dan.carpenter@linaro.org, kernel-janitors@vger.kernel.org,
        Rob Clark <robdclark@gmail.com>,
        Abhinav Kumar <quic_abhinavk@quicinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@linaro.org>,
        Sean Paul <sean@poorly.run>,
        Marijn Suijten <marijn.suijten@somainline.org>,
        David Airlie <airlied@gmail.com>,
        Daniel Vetter <daniel@ffwll.ch>,
        Mukesh Ojha <quic_mojha@quicinc.com>,
        Douglas Anderson <dianders@chromium.org>,
        Akhil P Oommen <quic_akhilpo@quicinc.com>,
        Adam Skladowski <a39.skl@gmail.com>,
        Elliot Berman <quic_eberman@quicinc.com>,
        linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org,
        freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org
Subject: [PATCH next] drm/msm/a5xx: Fix a NULL dereference bug in a5xx_gpu_init()
Date:   Mon, 26 Jun 2023 21:12:35 -0700
Message-ID: <20230627041250.3899791-1-harshit.m.mogalapalli@oracle.com>
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Smatch complains:
	drivers/gpu/drm/msm/adreno/a5xx_gpu.c:1753
	a5xx_gpu_init() warn: variable dereferenced before
	check 'pdev' (see line 1746)

When no device is defined, dereferencing pdev is a NULL dereference.
Fix this by dereferencing pdev to get the config post the NULL check.

Fixes: 736a93273656 ("drm/msm/a5xx: really check for A510 in a5xx_gpu_init")
Signed-off-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com>
---
This is based on static analysis, only compile tested.
---
 drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
index a99310b68793..adaf8f8e7f2d 100644
--- a/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a5xx_gpu.c
@@ -1743,7 +1743,7 @@ struct msm_gpu *a5xx_gpu_init(struct drm_device *dev)
 {
 	struct msm_drm_private *priv = dev->dev_private;
 	struct platform_device *pdev = priv->gpu_pdev;
-	struct adreno_platform_config *config = pdev->dev.platform_data;
+	struct adreno_platform_config *config;
 	struct a5xx_gpu *a5xx_gpu = NULL;
 	struct adreno_gpu *adreno_gpu;
 	struct msm_gpu *gpu;
@@ -1755,6 +1755,8 @@ struct msm_gpu *a5xx_gpu_init(struct drm_device *dev)
 		return ERR_PTR(-ENXIO);
 	}
 
+	config = pdev->dev.platform_data;
+
 	a5xx_gpu = kzalloc(sizeof(*a5xx_gpu), GFP_KERNEL);
 	if (!a5xx_gpu)
 		return ERR_PTR(-ENOMEM);
-- 
2.39.3