diff --git a/tools/verification/rvgen/rvgen/kunit.py b/tools/verification/rvgen/rvgen/kunit.py
index ed2082d7d3bc..85973f918c9b 100644
--- a/tools/verification/rvgen/rvgen/kunit.py
+++ b/tools/verification/rvgen/rvgen/kunit.py
@@ -173,7 +173,7 @@ EXPORT_SYMBOL_IF_KUNIT({struct_name});
             for path in (header_file_path, kunit_c_file_path):
                 if path.exists():
                     try:
-                        path.rename(path.with_suffix(path.suffix + ".bak"))
+                        path.rename(path.with_suffix(path.suffix + ".old"))
                     except OSError as e:
                         raise KUnitError(f"Error backing up file {path}: {e}") from e
 
diff --git a/tools/verification/rvgen/tests/golden/test_bak_kunit/test_bak_kunit_kunit.c.bak b/tools/verification/rvgen/tests/golden/test_bak_kunit/test_bak_kunit_kunit.c.old
similarity index 100%
rename from tools/verification/rvgen/tests/golden/test_bak_kunit/test_bak_kunit_kunit.c.bak
rename to tools/verification/rvgen/tests/golden/test_bak_kunit/test_bak_kunit_kunit.c.old