diff --git a/tests/guest-debug/test-gdbstub.py b/tests/guest-debug/test-gdbstub.py
index 0e4ac01426..c7e3986a24 100644
--- a/tests/guest-debug/test-gdbstub.py
+++ b/tests/guest-debug/test-gdbstub.py
@@ -16,6 +16,7 @@ def report(cond, msg):
         print ("PASS: %s" % (msg))
     else:
         print ("FAIL: %s" % (msg))
+        global failcount
         failcount += 1