diff --git a/testsuite/driver/testlib.py b/testsuite/driver/testlib.py
index c1bc44de3adf1f4a933deee0484362b39eb29517..372539d67beae1661133eeba0a9bd70804caa900 100644
--- a/testsuite/driver/testlib.py
+++ b/testsuite/driver/testlib.py
@@ -726,10 +726,12 @@ def _find_so(lib, directory, in_place):
 
     # produce the suffix for the CI operating system
     suffix = "so"
-    if config.os == "mingw32":
-        suffix = "dll"
-    elif config.os == "darwin":
-        suffix = "dylib"
+    # config.os is host os
+    if not config.cross:
+        if config.os == "mingw32":
+            suffix = "dll"
+        elif config.os == "darwin":
+            suffix = "dylib"
 
     # Most artfacts are of the form foo-inplace, except for the rts.
     if in_place: