diff --git a/lib/spack/spack/platforms/linux.py b/lib/spack/spack/platforms/linux.py
index ebe018812ac..4d8adac3849 100644
--- a/lib/spack/spack/platforms/linux.py
+++ b/lib/spack/spack/platforms/linux.py
@@ -14,7 +14,7 @@ def __init__(self):
         linux_dist = LinuxDistro()
         self.default_os = str(linux_dist)
         self.front_os = self.default_os
-        self.back_os = self.default._os
+        self.back_os = self.default_os
         self.add_operating_system(str(linux_dist), linux_dist)
 
     @classmethod