[PATCH] drm/amd: 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..c85bb313e6df 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c
@@ -1420,6 +1420,8 @@ int amdgpu_cs_fence_to_handle_ioctl(struct drm_device *dev, void *data,
 	fence = amdgpu_cs_get_fence(adev, filp, &info->in.fence);
 	if (IS_ERR(fence))
 		return PTR_ERR(fence);
+	if (!fence)
+		return -EINVAL;
 
 	switch (info->in.what) {
 	case AMDGPU_FENCE_TO_HANDLE_GET_SYNCOBJ:
-- 
2.15.1