[PATCH AUTOSEL for 4.15 038/124] drm/msm: Fix NULL deref in adreno_load_gpu

Sasha Levin
2018-03-19T22:30:02Z

From: Archit Taneja <architt@codeaurora.org>

[ Upstream commit 9dcfbc182f1aac0aa5ea194733d21e67dd2ba1fd ]

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.

v2: Incorporate Jordan's comments:
- Simplify the check to share the same error message.
- Use dev_err_once() to avoid an error message every time we open the
drm device fd.

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

Signed-off-by: Archit Taneja <architt@codeaurora.org>
Acked-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
drivers/gpu/drm/msm/adreno/adreno_device.c | 7 +++++--
1 file changed, 5 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..bfb3d689f47d 100644
--- a/drivers/gpu/drm/msm/adreno/adreno_device.c
+++ b/drivers/gpu/drm/msm/adreno/adreno_device.c
@@ -125,11 +125,14 @@ 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 msm_gpu *gpu = NULL;
int ret;

+ if (pdev)
+ gpu = platform_get_drvdata(pdev);
+
if (!gpu) {
- dev_err(dev->dev, "no adreno device\n");
+ dev_err_once(dev->dev, "no GPU device was found\n");
return NULL;
}

--
2.14.1