diff --git a/src/buffer.c b/src/buffer.c
index 13861a8edbb..c533d4343fa 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -457,6 +457,9 @@ reset_buffer (b)
   b->point_before_scroll = Qnil;
   b->file_format = Qnil;
   b->redisplay_end_trigger = Qnil;
+  b->extra1 = Qnil;
+  b->extra2 = Qnil;
+  b->extra3 = Qnil;
 }
 
 /* Reset buffer B's local variables info.