diff --git a/fs/proc/array.c b/fs/proc/array.c
index 0c6bc60..07f77a7 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -322,6 +322,8 @@
 			p->nivcsw);
 }
 
+#ifdef CONFIG_MMU
+
 struct stack_stats {
 	struct vm_area_struct *vma;
 	unsigned long	startpage;
@@ -402,6 +404,11 @@
 		mmput(mm);
 	}
 }
+#else
+static void task_show_stack_usage(struct seq_file *m, struct task_struct *task)
+{
+}
+#endif		/* CONFIG_MMU */
 
 int proc_pid_status(struct seq_file *m, struct pid_namespace *ns,
 			struct pid *pid, struct task_struct *task)