From 09baeec0dabc24050f344272ed36e39687c2b4e8 Mon Sep 17 00:00:00 2001
From: Zsolt Felfoldi <zsfelfoldi@gmail.com>
Date: Fri, 11 Nov 2016 03:10:46 +0100
Subject: [PATCH 1/2] discv5: fixed state machine lockup bug

---
 p2p/discv5/net.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/p2p/discv5/net.go b/p2p/discv5/net.go
index afc92e99fb..b08cd2bc76 100644
--- a/p2p/discv5/net.go
+++ b/p2p/discv5/net.go
@@ -863,6 +863,9 @@ func init() {
 		name: "verifywait",
 		handle: func(net *Network, n *Node, ev nodeEvent, pkt *ingressPacket) (*nodeState, error) {
 			switch ev {
+			case pingPacket:
+				net.handlePing(n, pkt)
+				return verifywait, nil
 			case pongPacket:
 				err := net.handleKnownPong(n, pkt)
 				return known, err

From 323c2d6775c86c063e9048ef0e8605283f07cafb Mon Sep 17 00:00:00 2001
From: Zsolt Felfoldi <zsfelfoldi@gmail.com>
Date: Fri, 11 Nov 2016 03:16:46 +0100
Subject: [PATCH 2/2] les: add missing nil check and handle quit in findServers

---
 les/handler.go | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/les/handler.go b/les/handler.go
index 44a0a1661b..cf698d79cd 100644
--- a/les/handler.go
+++ b/les/handler.go
@@ -236,7 +236,7 @@ func (pm *ProtocolManager) removePeer(id string) {
 }
 
 func (pm *ProtocolManager) findServers() {
-	if pm.p2pServer == nil {
+	if pm.p2pServer == nil || pm.topicDisc == nil {
 		return
 	}
 	enodes := make(chan string, 100)
@@ -259,7 +259,10 @@ func (pm *ProtocolManager) findServers() {
 			}
 		}
 	}()
-	time.Sleep(time.Second * 20)
+	select {
+	case <-time.After(time.Second * 20):
+	case <-pm.quitSync:
+	}
 	close(stop)
 }