diff --git a/src/osmo_gsm_tester/core/process.py b/src/osmo_gsm_tester/core/process.py
index 33ae69a..8954674 100644
--- a/src/osmo_gsm_tester/core/process.py
+++ b/src/osmo_gsm_tester/core/process.py
@@ -347,7 +347,7 @@
         return self.result is not None
 
     def wait(self, timeout=300):
-        MainLoop.wait(self, self.terminated, timeout=timeout)
+        MainLoop.wait(self.terminated, timeout=timeout)
 
     def stdin_write(self, cmd):
         '''