1 files changed, 4 insertions, 2 deletions
diff --git a/kalloc.c b/kalloc.c
index 14cd4f4..fb939b7 100644
--- a/kalloc.c
+++ b/kalloc.c
@@ -47,7 +47,7 @@ void
 freerange(void *vstart, void *vend)
 {
   char *p;
-  p = (char*)PGROUNDUP((uint)vstart);
+  p = (char*)PGROUNDUP((uint64)vstart);
   for(; p + PGSIZE <= (char*)vend; p += PGSIZE)
     kfree(p);
 }
@@ -61,7 +61,7 @@ kfree(char *v)
 {
   struct run *r;
 
-  if((uint)v % PGSIZE || v < end || V2P(v) >= PHYSTOP)
+  if((uint64)v % PGSIZE || v < end || V2P(v) >= PHYSTOP)
     panic("kfree");
 
   // Fill with junk to catch dangling refs.
@@ -91,6 +91,8 @@ kalloc(void)
     kmem.freelist = r->next;
   if(kmem.use_lock)
     release(&kmem.lock);
+  if(r != 0 && (uint64) r < KERNBASE)
+    panic("kalloc");
   return (char*)r;
 }