From 2099d6fa77861ef10f19efff16e7efcc0ca3a49d Mon Sep 17 00:00:00 2001
From: Olaoluwa Osuntokun <laolu32@gmail.com>
Date: Mon, 5 Feb 2018 14:41:03 -0800
Subject: [PATCH] contractcourt: ensure we always cancel block epoch
 notifications after use
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In this commit, we fix an existing grouting leak within the contract
court package. If a goroutine dies, but it doesn’t actually cancel the
block epoch notification that it requested, then it’s possible to leak
thousands of gorutines. To remedy this situation, we ensure that we’ll
*always* cancel the epoch notification once the goroutine has exited.
---
 contractcourt/chain_arbitrator.go   | 1 +
 contractcourt/contract_resolvers.go | 7 ++++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/contractcourt/chain_arbitrator.go b/contractcourt/chain_arbitrator.go
index 0ba0d575..472a6deb 100644
--- a/contractcourt/chain_arbitrator.go
+++ b/contractcourt/chain_arbitrator.go
@@ -395,6 +395,7 @@ func (c *ChainArbitrator) Start() error {
 			c.chanSource.DB, arbCfg, c.cfg.ChainHash, chanPoint,
 		)
 		if err != nil {
+			blockEpoch.Cancel()
 			return err
 		}
 		arbCfg.MarkChannelResolved = func() error {
diff --git a/contractcourt/contract_resolvers.go b/contractcourt/contract_resolvers.go
index 92049eb5..2606a834 100644
--- a/contractcourt/contract_resolvers.go
+++ b/contractcourt/contract_resolvers.go
@@ -865,6 +865,8 @@ func (h *htlcOutgoingContestResolver) Resolve() (ContractResolver, error) {
 	if err != nil {
 		return nil, err
 	}
+	defer blockEpochs.Cancel()
+
 	for {
 		select {
 
@@ -1058,7 +1060,10 @@ func (h *htlcIncomingContestResolver) Resolve() (ContractResolver, error) {
 	if err != nil {
 		return nil, err
 	}
-	defer preimageSubscription.CancelSubcription()
+	defer func() {
+		preimageSubscription.CancelSubcription()
+		blockEpochs.Cancel()
+	}()
 	for {
 
 		select {