[PATCH] drm/msm: Fix NULL deref in adreno_load_gpu

[Archit Taneja <architt@codeaurora.org>]

The msm/kms driver should work even if there is no GPU device specified
in DT. Currently, we get a NULL dereference crash in adreno_load_gpu
since the driver assumes that priv->gpu_pdev is non-NULL.

Perform an additional check on priv->gpu_pdev before trying to retrieve
the msm_gpu pointer from it.

Fixes: eec874ce5ff1 (drm/msm/adreno: load gpu at probe/bind time)

Signed-off-by: Archit Taneja <architt@codeaurora.org>
---
 drivers/gpu/drm/msm/adreno/adreno_device.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/adreno_device.c b/drivers/gpu/drm/msm/adreno/adreno_device.c
index 05022ea2a007..ac60cf3c794e 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_device.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_device.c
@@ -124,10 +124,17 @@ const struct adreno_info *adreno_info(struct adreno_rev rev)
 struct msm_gpu *adreno_load_gpu(struct drm_device *dev)
 {
 	struct msm_drm_private *priv = dev->dev_private;
-	struct platform_device *pdev = priv->gpu_pdev;
-	struct msm_gpu *gpu = platform_get_drvdata(priv->gpu_pdev);
+	struct platform_device *pdev;
+	struct msm_gpu *gpu;
 	int ret;
 
+	pdev = priv->gpu_pdev;
+	if (!pdev) {
+		dev_dbg(dev->dev, "no adreno platform device found\n");
+		return NULL;
+	}
+
+	gpu = platform_get_drvdata(pdev);
 	if (!gpu) {
 		dev_err(dev->dev, "no adreno device\n");
 		return NULL;
-- 
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