diff --git a/src/or/dns.c b/src/or/dns.c
index fb05729fd5..2ef5aa7a24 100644
--- a/src/or/dns.c
+++ b/src/or/dns.c
@@ -633,7 +633,7 @@ int connection_dns_process_inbuf(connection_t *conn) {
   tor_assert(conn->type == CONN_TYPE_DNSWORKER);
 
   if (conn->state != DNSWORKER_STATE_BUSY && buf_datalen(conn->inbuf)) {
-    log_fn(LOG_WARN,"Bug: read data from an idle dns worker.  Please report.");
+    log_fn(LOG_WARN,"Bug: read data (%d bytes) from an idle dns worker.  Please report.", buf_datalen(conn->inbuf));
 #ifdef TOR_FRAGILE
     tor_assert(0);
 #endif