diff --git a/agent/call-scd.c b/agent/call-scd.c
index 796e7d86e..d0d4794a4 100644
--- a/agent/call-scd.c
+++ b/agent/call-scd.c
@@ -275,7 +275,7 @@ wait_child_thread (void *arg)
 
       err = npth_mutex_unlock (&start_scd_lock);
       if (err)
-        log_error ("failed to release the start_scd lock after waitpid",
+        log_error ("failed to release the start_scd lock after waitpid: %s\n",
                    strerror (err));
     }