[PATCH] drm/amdgpu: add the checking to avoid NULL pointer dereference

[Sharma, Deepak]

when returned fence is not valid mostly due to userspace ignored
previous error causes NULL pointer dereference.

Signed-off-by: Deepak Sharma <Deepak.Sharma at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
index 024dfbd87f11..14166cd8a12f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -1403,6 +1403,8 @@ static struct dma_fence *amdgpu_cs_get_fence(struct amdgpu_device *adev,
 
 	fence = amdgpu_ctx_get_fence(ctx, entity, user->seq_no);
 	amdgpu_ctx_put(ctx);
+	if(!fence)
+		return ERR_PTR(-EINVAL);
 
 	return fence;
 }
-- 
2.15.1