diff --git a/mm/nommu.c b/mm/nommu.c
index 989e2e9..8bbbf14 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -367,6 +367,11 @@
 	return find_vma(mm, addr);
 }
 
+int expand_stack(struct vm_area_struct *vma, unsigned long address)
+{
+	return -ENOMEM;
+}
+
 /*
  * look up the first VMA exactly that exactly matches addr
  * - should be called with mm->mmap_sem at least held readlocked