From a9b863ea51bad2af8b2b9d129e36c1838b9a02db Mon Sep 17 00:00:00 2001
From: Felix Lange <fjl@twurst.com>
Date: Mon, 8 Jul 2019 15:33:48 +0200
Subject: [PATCH] eth: fix crash in ethclient tests

---
 eth/backend.go   |  2 +-
 eth/enr_entry.go | 24 +++++++++++++-----------
 2 files changed, 14 insertions(+), 12 deletions(-)

diff --git a/eth/backend.go b/eth/backend.go
index 052bfad0f9..dc4ff8ade8 100644
--- a/eth/backend.go
+++ b/eth/backend.go
@@ -522,7 +522,7 @@ func (s *Ethereum) Protocols() []p2p.Protocol {
 // Start implements node.Service, starting all internal goroutines needed by the
 // Ethereum protocol implementation.
 func (s *Ethereum) Start(srvr *p2p.Server) error {
-	go s.enrUpdateLoop(srvr.LocalNode())
+	s.startEthEntryUpdate(srvr.LocalNode())
 
 	// Start the bloom bits servicing goroutines
 	s.startBloomHandlers(params.BloomBitsBlocks)
diff --git a/eth/enr_entry.go b/eth/enr_entry.go
index 3798440da4..d9e7b95784 100644
--- a/eth/enr_entry.go
+++ b/eth/enr_entry.go
@@ -37,21 +37,23 @@ func (e ethEntry) ENRKey() string {
 	return "eth"
 }
 
-func (eth *Ethereum) enrUpdateLoop(ln *enode.LocalNode) {
+func (eth *Ethereum) startEthEntryUpdate(ln *enode.LocalNode) {
 	var newHead = make(chan core.ChainHeadEvent, 10)
 	sub := eth.blockchain.SubscribeChainHeadEvent(newHead)
-	defer sub.Unsubscribe()
 
-	for {
-		select {
-		case <-newHead:
-			ln.Set(eth.currentEthEntry())
-		case <-sub.Err():
-			// Would be nice to sync with eth.Stop, but there is no
-			// good way to do that.
-			return
+	go func() {
+		defer sub.Unsubscribe()
+		for {
+			select {
+			case <-newHead:
+				ln.Set(eth.currentEthEntry())
+			case <-sub.Err():
+				// Would be nice to sync with eth.Stop, but there is no
+				// good way to do that.
+				return
+			}
 		}
-	}
+	}()
 }
 
 func (eth *Ethereum) currentEthEntry() *ethEntry {