diff --git a/kernel/proc.c b/kernel/proc.c
index 580b3b6..3bb2618 100644
--- a/kernel/proc.c
+++ b/kernel/proc.c
@@ -259,7 +259,7 @@ userinit(void)
 int
 growproc(int n)
 {
-  uint sz;
+  uint64 sz;
   struct proc *p = myproc();
 
   sz = p->sz;
diff --git a/kernel/sysproc.c b/kernel/sysproc.c
index 8ca45ba..c74def2 100644
--- a/kernel/sysproc.c
+++ b/kernel/sysproc.c
@@ -40,7 +40,7 @@ sys_wait(void)
 uint64
 sys_sbrk(void)
 {
-  int addr;
+  uint64 addr;
   int n;
 
   if(argint(0, &n) < 0)