2 files changed, 21 insertions, 4 deletions

diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
index 5d05093014ac..9f4a90493aea 100644
--- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c
+++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c
@@ -358,10 +358,18 @@ static int virtio_gpu_resource_create_ioctl(struct drm_device *dev, void *data,
 		drm_gem_object_release(obj);
 		return ret;
 	}
-	drm_gem_object_put(obj);
 
 	rc->res_handle = qobj->hw_res_handle; /* similiar to a VM address */
 	rc->bo_handle = handle;
+
+	/*
+	 * The handle owns the reference now.  But we must drop our
+	 * remaining reference *after* we no longer need to dereference
+	 * the obj.  Otherwise userspace could guess the handle and
+	 * race closing it from another thread.
+	 */
+	drm_gem_object_put(obj);
+
 	return 0;
 }
 
@@ -723,11 +731,18 @@ static int virtio_gpu_resource_create_blob_ioctl(struct drm_device *dev,
 		drm_gem_object_release(obj);
 		return ret;
 	}
-	drm_gem_object_put(obj);
 
 	rc_blob->res_handle = bo->hw_res_handle;
 	rc_blob->bo_handle = handle;
 
+	/*
+	 * The handle owns the reference now.  But we must drop our
+	 * remaining reference *after* we no longer need to dereference
+	 * the obj.  Otherwise userspace could guess the handle and
+	 * race closing it from another thread.
+	 */
+	drm_gem_object_put(obj);
+
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c
index 8d7728181de0..c7e74cf13022 100644
--- a/drivers/gpu/drm/virtio/virtgpu_object.c
+++ b/drivers/gpu/drm/virtio/virtgpu_object.c
@@ -184,7 +184,7 @@ int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
 	struct virtio_gpu_object_array *objs = NULL;
 	struct drm_gem_shmem_object *shmem_obj;
 	struct virtio_gpu_object *bo;
-	struct virtio_gpu_mem_entry *ents;
+	struct virtio_gpu_mem_entry *ents = NULL;
 	unsigned int nents;
 	int ret;
 
@@ -210,7 +210,7 @@ int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
 		ret = -ENOMEM;
 		objs = virtio_gpu_array_alloc(1);
 		if (!objs)
-			goto err_put_id;
+			goto err_free_entry;
 		virtio_gpu_array_add_obj(objs, &bo->base.base);
 
 		ret = virtio_gpu_array_lock_resv(objs);
@@ -239,6 +239,8 @@ int virtio_gpu_object_create(struct virtio_gpu_device *vgdev,
 
 err_put_objs:
 	virtio_gpu_array_put_free(objs);
+err_free_entry:
+	kvfree(ents);
 err_put_id:
 	virtio_gpu_resource_id_put(vgdev, bo->hw_res_handle);
 err_free_gem: