--- a/arch/um/os-Linux/start_up.c
+++ b/arch/um/os-Linux/start_up.c
@@ -15,6 +15,7 @@
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/wait.h>
+#include <sys/resource.h>
#include <asm/unistd.h>
#include "init.h"
#include "os.h"