diff --git a/lib/devise/rails/warden_compat.rb b/lib/devise/rails/warden_compat.rb
index 1e2aca5f..125e979d 100644
--- a/lib/devise/rails/warden_compat.rb
+++ b/lib/devise/rails/warden_compat.rb
@@ -31,7 +31,7 @@ class Warden::SessionSerializer
       record if record && record.authenticatable_salt == salt
     rescue NameError => e
       if e.message =~ /uninitialized constant/
-        Rails.logger.debug "Trying to deserialize invalid class #{klass}"
+        Rails.logger.debug "[Devise] Trying to deserialize invalid class #{klass}"
         nil
       else
         raise