diff --git a/hermit/arch/x86/mm/page.c b/hermit/arch/x86/mm/page.c
index f2b62aa3d..9c415a620 100644
--- a/hermit/arch/x86/mm/page.c
+++ b/hermit/arch/x86/mm/page.c
@@ -173,7 +173,7 @@ out:
 
 int page_unmap(size_t viraddr, size_t npages)
 {
-	//uint8_t ipi = 0;
+	uint8_t ipi = 0;
 
 	spinlock_irqsave_lock(&page_lock);
 
@@ -186,11 +186,8 @@ int page_unmap(size_t viraddr, size_t npages)
 		//ipi = 1;
 	}
 
-	/*
-	 * IPI isn't required because unmaping is only used by shutdown the system
-	 */
-	/*if (ipi)
-		ipi_tlb_flush();*/
+	if (ipi)
+		ipi_tlb_flush();
 
 	spinlock_irqsave_unlock(&page_lock);
 
diff --git a/hermit/mm/malloc.c b/hermit/mm/malloc.c
index acd2ec4b3..204a358d5 100644
--- a/hermit/mm/malloc.c
+++ b/hermit/mm/malloc.c
@@ -223,9 +223,11 @@ int destroy_stack(void* viraddr, size_t sz)
 		return -ENOMEM;
 
 	// unmap and destroy stack
+	int8_t flag = irq_nested_disable();
 	vma_free((size_t)viraddr-PAGE_SIZE, (size_t)viraddr+(npages+1)*PAGE_SIZE);
 	page_unmap((size_t)viraddr, npages);
 	put_pages(phyaddr, npages);
+	irq_nested_enable(flag);
 
 	return 0;
 }