diff --git a/vm.c b/vm.c
index 3e52b44..f2251ac 100644
--- a/vm.c
+++ b/vm.c
@@ -77,7 +77,7 @@ mappages(pde_t *pgdir, void *va, uint size, uint pa,
   a = (char*)PGROUNDDOWN((uint)va);
   last = (char*)PGROUNDDOWN(((uint)va) + size - 1);
   for(;;){
-    if((pte = walkpgdir(pgdir, a, alloc) == 0)
+    if((pte = walkpgdir(pgdir, a, alloc)) == 0)
       return -1;
     if(*pte & PTE_P)
       panic("remap");