diff --git a/tempest/stress/driver.py b/tempest/stress/driver.py
index e8ccc7c..517cfd5 100644
--- a/tempest/stress/driver.py
+++ b/tempest/stress/driver.py
@@ -198,9 +198,9 @@
 
             time.sleep(min(remaining, log_check_interval))
             if stop_on_error:
-                for process in processes:
-                    if process['statistic']['fails'] > 0:
-                        break
+                if any([True for proc in processes
+                        if proc['statistic']['fails'] > 0]):
+                    break
 
             if not logfiles:
                 continue