From 96c2ab22e0980f1aa0767abe14f9306badd28538 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?P=C3=A9ter=20Szil=C3=A1gyi?= <peterke@gmail.com>
Date: Tue, 2 May 2017 16:14:35 +0300
Subject: [PATCH] eth/downloader: fix a potential issue against future
 refactors

---
 eth/downloader/downloader.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/eth/downloader/downloader.go b/eth/downloader/downloader.go
index d26995782..839969f03 100644
--- a/eth/downloader/downloader.go
+++ b/eth/downloader/downloader.go
@@ -1491,6 +1491,10 @@ func (d *Downloader) qosTuner() {
 func (d *Downloader) qosReduceConfidence() {
 	// If we have a single peer, confidence is always 1
 	peers := uint64(d.peers.Len())
+	if peers == 0 {
+		// Ensure peer connectivity races don't catch us off guard
+		return
+	}
 	if peers == 1 {
 		atomic.StoreUint64(&d.rttConfidence, 1000000)
 		return