From d28bcc655bf0eb524584d09b8caae2f549bb7ba6 Mon Sep 17 00:00:00 2001
From: Martin Holst Swende <martin@swende.se>
Date: Wed, 31 Aug 2022 17:58:18 +0200
Subject: [PATCH] eth/protocols/snap: fix problems due to idle-but-busy peers

---
 eth/protocols/snap/sync.go | 90 +++++++++++++++++++++++---------------
 trie/sync.go               |  2 +-
 2 files changed, 56 insertions(+), 36 deletions(-)

diff --git a/eth/protocols/snap/sync.go b/eth/protocols/snap/sync.go
index 133acfaa0b..6a6105fccf 100644
--- a/eth/protocols/snap/sync.go
+++ b/eth/protocols/snap/sync.go
@@ -2252,14 +2252,18 @@ func (s *Syncer) OnAccounts(peer SyncPeer, id uint64, hashes []common.Hash, acco
 	// Whether or not the response is valid, we can mark the peer as idle and
 	// notify the scheduler to assign a new task. If the response is invalid,
 	// we'll drop the peer in a bit.
+	defer func() {
+		s.lock.Lock()
+		defer s.lock.Unlock()
+		if _, ok := s.peers[peer.ID()]; ok {
+			s.accountIdlers[peer.ID()] = struct{}{}
+		}
+		select {
+		case s.update <- struct{}{}:
+		default:
+		}
+	}()
 	s.lock.Lock()
-	if _, ok := s.peers[peer.ID()]; ok {
-		s.accountIdlers[peer.ID()] = struct{}{}
-	}
-	select {
-	case s.update <- struct{}{}:
-	default:
-	}
 	// Ensure the response is for a valid request
 	req, ok := s.accountReqs[id]
 	if !ok {
@@ -2364,14 +2368,18 @@ func (s *Syncer) onByteCodes(peer SyncPeer, id uint64, bytecodes [][]byte) error
 	// Whether or not the response is valid, we can mark the peer as idle and
 	// notify the scheduler to assign a new task. If the response is invalid,
 	// we'll drop the peer in a bit.
+	defer func() {
+		s.lock.Lock()
+		defer s.lock.Unlock()
+		if _, ok := s.peers[peer.ID()]; ok {
+			s.bytecodeIdlers[peer.ID()] = struct{}{}
+		}
+		select {
+		case s.update <- struct{}{}:
+		default:
+		}
+	}()
 	s.lock.Lock()
-	if _, ok := s.peers[peer.ID()]; ok {
-		s.bytecodeIdlers[peer.ID()] = struct{}{}
-	}
-	select {
-	case s.update <- struct{}{}:
-	default:
-	}
 	// Ensure the response is for a valid request
 	req, ok := s.bytecodeReqs[id]
 	if !ok {
@@ -2473,14 +2481,18 @@ func (s *Syncer) OnStorage(peer SyncPeer, id uint64, hashes [][]common.Hash, slo
 	// Whether or not the response is valid, we can mark the peer as idle and
 	// notify the scheduler to assign a new task. If the response is invalid,
 	// we'll drop the peer in a bit.
+	defer func() {
+		s.lock.Lock()
+		defer s.lock.Unlock()
+		if _, ok := s.peers[peer.ID()]; ok {
+			s.storageIdlers[peer.ID()] = struct{}{}
+		}
+		select {
+		case s.update <- struct{}{}:
+		default:
+		}
+	}()
 	s.lock.Lock()
-	if _, ok := s.peers[peer.ID()]; ok {
-		s.storageIdlers[peer.ID()] = struct{}{}
-	}
-	select {
-	case s.update <- struct{}{}:
-	default:
-	}
 	// Ensure the response is for a valid request
 	req, ok := s.storageReqs[id]
 	if !ok {
@@ -2600,14 +2612,18 @@ func (s *Syncer) OnTrieNodes(peer SyncPeer, id uint64, trienodes [][]byte) error
 	// Whether or not the response is valid, we can mark the peer as idle and
 	// notify the scheduler to assign a new task. If the response is invalid,
 	// we'll drop the peer in a bit.
+	defer func() {
+		s.lock.Lock()
+		defer s.lock.Unlock()
+		if _, ok := s.peers[peer.ID()]; ok {
+			s.trienodeHealIdlers[peer.ID()] = struct{}{}
+		}
+		select {
+		case s.update <- struct{}{}:
+		default:
+		}
+	}()
 	s.lock.Lock()
-	if _, ok := s.peers[peer.ID()]; ok {
-		s.trienodeHealIdlers[peer.ID()] = struct{}{}
-	}
-	select {
-	case s.update <- struct{}{}:
-	default:
-	}
 	// Ensure the response is for a valid request
 	req, ok := s.trienodeHealReqs[id]
 	if !ok {
@@ -2695,14 +2711,18 @@ func (s *Syncer) onHealByteCodes(peer SyncPeer, id uint64, bytecodes [][]byte) e
 	// Whether or not the response is valid, we can mark the peer as idle and
 	// notify the scheduler to assign a new task. If the response is invalid,
 	// we'll drop the peer in a bit.
+	defer func() {
+		s.lock.Lock()
+		defer s.lock.Unlock()
+		if _, ok := s.peers[peer.ID()]; ok {
+			s.bytecodeHealIdlers[peer.ID()] = struct{}{}
+		}
+		select {
+		case s.update <- struct{}{}:
+		default:
+		}
+	}()
 	s.lock.Lock()
-	if _, ok := s.peers[peer.ID()]; ok {
-		s.bytecodeHealIdlers[peer.ID()] = struct{}{}
-	}
-	select {
-	case s.update <- struct{}{}:
-	default:
-	}
 	// Ensure the response is for a valid request
 	req, ok := s.bytecodeHealReqs[id]
 	if !ok {
diff --git a/trie/sync.go b/trie/sync.go
index 10eaeb53da..d45f2c31bc 100644
--- a/trie/sync.go
+++ b/trie/sync.go
@@ -417,7 +417,7 @@ func (s *Sync) children(req *request, object node) ([]*request, error) {
 				missing <- &request{
 					path:     child.path,
 					hash:     chash,
-					parents:   []*request{req},
+					parents:  []*request{req},
 					callback: req.callback,
 				}
 			}(child)