From: Saarett <Saarett@users.noreply.github.com>
Date: Sun, 5 Feb 2017 10:44:56 +0000 (+0200)
Subject: Free pgdir in setupkvm in case of mappages failure
X-Git-Url: https://git.devinivas.org/?a=commitdiff_plain;h=03b30863279b111fb6b9f154a9bdaa831114adfb;p=cs3210-lab0.git

Free pgdir in setupkvm in case of mappages failure

There is a potential memory leak when mappages() fails inside setupkvm().
A call to freevm() is added in this case so as to reclaim the lost mapping pages.
---

diff --git a/vm.c b/vm.c
index 9db8b67..39642f4 100644
--- a/vm.c
+++ b/vm.c
@@ -137,8 +137,10 @@ setupkvm(void)
     panic("PHYSTOP too high");
   for(k = kmap; k < &kmap[NELEM(kmap)]; k++)
     if(mappages(pgdir, k->virt, k->phys_end - k->phys_start,
-                (uint)k->phys_start, k->perm) < 0)
+                (uint)k->phys_start, k->perm) < 0) {
+      freevm(pgdir);
       return 0;
+    }
   return pgdir;
 }