diff --git a/tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c b/tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c
index 890a8236a8ba..2809f9a25c43 100644
--- a/tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c
+++ b/tools/testing/selftests/dmabuf-heaps/dmabuf-heap.c
@@ -28,9 +28,11 @@ static int check_vgem(int fd)
 	version.name = name;
 
 	ret = ioctl(fd, DRM_IOCTL_VERSION, &version);
-	if (ret)
+	if (ret || version.name_len != 4)
 		return 0;
 
+	name[4] = '\0';
+
 	return !strcmp(name, "vgem");
 }