torrent.go | 3 +++

diff --git a/torrent.go b/torrent.go
index 927b25fdbdce28d07cc1ebab9992ed89c1393136..195027a3cca0f36a6b12eed3f162d1bc18281793 100644
--- a/torrent.go
+++ b/torrent.go
@@ -377,6 +377,9 @@ 	t.length = &l
 }
 
 func (t *Torrent) setInfo(info *metainfo.Info) error {
+	if t.info != nil {
+		return errors.New("info already set")
+	}
 	if err := validateInfo(info); err != nil {
 		return fmt.Errorf("bad info: %s", err)
 	}