clear np->mem after freeing

diff --git a/proc.c b/proc.c
index d90b057658027dc955870867ebb477bc5a6b96ba..3fd35d5dbe9910e40d72eacbb7033962c51dbe6f 100644 (file)
--- a/proc.c
+++ b/proc.c
@@ -107,6 +107,7 @@ copyproc(struct proc* p)
   np->kstack = kalloc(KSTACKSIZE);
   if(np->kstack == 0){
     kfree(np->mem, np->sz);
+    np->mem = 0;
     np->state = UNUSED;
     return 0;
   }