diff --git a/src/linux/mod.rs b/src/linux/mod.rs
index ef57868..97c648b 100644
--- a/src/linux/mod.rs
+++ b/src/linux/mod.rs
@@ -134,9 +134,11 @@ impl Sandbox for LinuxSandbox {
         }
 
         // Use landlock only if namespaces failed.
-        if namespace_result.is_ok() {
-            return Ok(());
-        }
+        namespace_result.unwrap();
+        println!("NAMESPACE OK");
+        // if namespace_result.is_ok() {
+        //     return Ok(());
+        // }
 
         // Apply landlock rules.
         let status = self.landlock.restrict_self()?;
diff --git a/tests/fs_without_landlock.rs b/tests/fs_without_landlock.rs
index 391b81c..e981838 100644
--- a/tests/fs_without_landlock.rs
+++ b/tests/fs_without_landlock.rs
@@ -52,6 +52,7 @@ fn main() {
     // Access to the private file is prohibited.
     let result = fs::read_to_string(private_path);
     assert!(result.is_err());
+    panic!();
 }
 
 #[cfg(not(target_os = "linux"))]