Fix similar leak in copyuvm

ba04b3e7 · Austin Clements · dd645ef1 · ba04b3e7
--- a/vm.c
+++ b/vm.c
@@ -313,13 +313,17 @@ copyuvm(pde_t *pgdir, uint sz)
    if(*pte & PTE_P){
      pa = PTE_ADDR(*pte);
      if (!(mem = kalloc()))
-        return 0;
+        goto bad;
      memmove(mem, (char *)pa, PGSIZE);
      if (!mappages(d, (void *)i, PGSIZE, PADDR(mem), PTE_W|PTE_U))
-        return 0;
+        goto bad;
    }
  }
  return d;
+bad:
+  freevm(d);
+  return 0;
 }
 // Allocate one page table for the machine for the kernel address