X-Git-Url: https://pintos-os.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=src%2Fuserprog%2Fpagedir.c;h=1edd0ff1931f84888a922558fe73ac0f78365f95;hb=c9d2f441f65d0c3a92938df02a752e6c78de487d;hp=bfcda457512574f85f06b1c950a08fe15117621a;hpb=e49318880e6420e9b5a4ae9ffb986b49f89798e0;p=pintos-anon

diff --git a/src/userprog/pagedir.c b/src/userprog/pagedir.c
index bfcda45..1edd0ff 100644
--- a/src/userprog/pagedir.c
+++ b/src/userprog/pagedir.c
@@ -19,6 +19,9 @@ pagedir_destroy (uint32_t *pd)
 {
   uint32_t *pde;
 
+  if (pd == NULL)
+    return;
+
   for (pde = pd; pde < pd + pd_no (PHYS_BASE); pde++)
     if (*pde & PG_P) 
       {