From 450a152b240a3d2cfb89a01e92b3a3ce8885d7c2 Mon Sep 17 00:00:00 2001
From: Stephen Marz <stephen.marz@utk.edu>
Date: Thu, 10 Oct 2019 08:45:39 -0400
Subject: [PATCH] Add sanity check from kmalloc. Don't zero if it is null

---
 risc_v/ch3/src/kmem.rs | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/risc_v/ch3/src/kmem.rs b/risc_v/ch3/src/kmem.rs
index 4dd04f0..504076b 100644
--- a/risc_v/ch3/src/kmem.rs
+++ b/risc_v/ch3/src/kmem.rs
@@ -87,9 +87,11 @@ pub fn kzmalloc(sz: usize) -> *mut u8 {
 	let size = align_val(sz, 3);
 	let ret = kmalloc(size);
 
-	for i in 0..size {
-		unsafe {
-			(*ret.add(i)) = 0;
+	if !ret.is_null() {
+		for i in 0..size {
+			unsafe {
+				(*ret.add(i)) = 0;
+			}
 		}
 	}
 	ret