Nits on vm.c descend.

7518773e · Silas Boyd-Wickizer · 554c58e9 · 7518773e
--- a/vm.c
+++ b/vm.c
@@ -20,7 +20,7 @@ extern pml4e_t kpml4[];
 extern char* pgalloc(void);

 static pme_t*
-descend(pme_t *dir, void *va, u64 flags, int create, int level)
+descend(pme_t *dir, const void *va, u64 flags, int create, int level)
 {
  pme_t entry;
  pme_t *next;
@@ -36,6 +36,7 @@ retry:
    next = (pme_t*) pgalloc();
    if (!next)
      return NULL;
+    memset(next, 0, PGSIZE);
    if (!cmpswap(dir, entry, v2p(next) | PTE_P | PTE_W | flags)) {
      kfree((void*) next);
      goto retry;