diff --git a/devlib/module/cgroups.py b/devlib/module/cgroups.py
index e4b387c..dd514d9 100644
--- a/devlib/module/cgroups.py
+++ b/devlib/module/cgroups.py
@@ -448,6 +448,8 @@
 
         # Create Freezer CGroup
         freezer = self.controller('freezer')
+        if freezer is None:
+            raise RuntimeError('freezer cgroup controller not present')
         freezer_cg = freezer.cgroup('/DEVLIB_FREEZER')
         thawed_cg = freezer.cgroup('/')