diff --git a/trunk/src/or/connection_edge.c b/trunk/src/or/connection_edge.c
index 57f72e8808..4d36e07573 100644
--- a/trunk/src/or/connection_edge.c
+++ b/trunk/src/or/connection_edge.c
@@ -902,6 +902,8 @@ void client_dns_clean(void)
   time_t now;
   int i;
 
+  if(!client_dns_size)
+    return;
   expired_entries = tor_malloc(client_dns_size * 
                                sizeof(struct client_dns_entry *));