shell nits

fix Regehr complaint

1 files changed, 6 insertions, 1 deletions

diff --git a/vm.c b/vm.c
index 5326d14..85f6ce2 100644
--- a/vm.c
+++ b/vm.c
@@ -237,7 +237,12 @@ allocuvm(pde_t *pgdir, uint oldsz, uint newsz)
       return 0;
     }
     memset(mem, 0, PGSIZE);
-    mappages(pgdir, (char*)a, PGSIZE, v2p(mem), PTE_W|PTE_U);
+    if(mappages(pgdir, (char*)a, PGSIZE, v2p(mem), PTE_W|PTE_U) < 0){
+      cprintf("allocuvm out of memory (2)\n");
+      deallocuvm(pgdir, newsz, oldsz);
+      kfree(mem);
+      return 0;
+    }
   }
   return newsz;
 }