From 8a5d6298bc49f9e680dd5a395b873b62f6c173e7 Mon Sep 17 00:00:00 2001
From: Luca Moser <moser.luca@gmail.com>
Date: Fri, 7 Feb 2020 09:47:21 +0100
Subject: [PATCH] Fixes deadlock in neighbor manager (#236)
* fixes locks not getting unlocked
* only hold the lock in DropNeighbor while deleted the neighbor entry
---
packages/gossip/manager.go | 31 +++++++++++++++++++------------
1 file changed, 19 insertions(+), 12 deletions(-)
diff --git a/packages/gossip/manager.go b/packages/gossip/manager.go
index 2a44ddd4..bc3d7222 100644
--- a/packages/gossip/manager.go
+++ b/packages/gossip/manager.go
@@ -78,6 +78,7 @@ func (m *Manager) AddOutbound(p *peer.Peer) error {
var srv *server.TCP
m.mu.RLock()
if m.srv == nil {
+ m.mu.RUnlock()
return ErrNotStarted
}
srv = m.srv
@@ -94,6 +95,7 @@ func (m *Manager) AddInbound(p *peer.Peer) error {
var srv *server.TCP
m.mu.RLock()
if m.srv == nil {
+ m.mu.RUnlock()
return ErrNotStarted
}
srv = m.srv
@@ -104,15 +106,11 @@ func (m *Manager) AddInbound(p *peer.Peer) error {
// NeighborRemoved disconnects the neighbor with the given ID.
func (m *Manager) DropNeighbor(id peer.ID) error {
- m.mu.Lock()
- defer m.mu.Unlock()
- if _, ok := m.neighbors[id]; !ok {
- return ErrNotANeighbor
+ n, err := m.removeNeighbor(id)
+ if err != nil {
+ return err
}
- n := m.neighbors[id]
- delete(m.neighbors, id)
-
- err := n.Close()
+ err = n.Close()
Events.NeighborRemoved.Trigger(n.Peer)
return err
}
@@ -139,12 +137,11 @@ func (m *Manager) SendTransaction(txData []byte, to ...peer.ID) {
func (m *Manager) GetAllNeighbors() []*Neighbor {
m.mu.RLock()
+ defer m.mu.RUnlock()
result := make([]*Neighbor, 0, len(m.neighbors))
for _, n := range m.neighbors {
result = append(result, n)
}
- m.mu.RUnlock()
-
return result
}
@@ -159,13 +156,12 @@ func (m *Manager) getNeighborsById(ids []peer.ID) []*Neighbor {
result := make([]*Neighbor, 0, len(ids))
m.mu.RLock()
+ defer m.mu.RUnlock()
for _, id := range ids {
if n, ok := m.neighbors[id]; ok {
result = append(result, n)
}
}
- m.mu.RUnlock()
-
return result
}
@@ -215,6 +211,17 @@ func (m *Manager) addNeighbor(peer *peer.Peer, connectorFunc func(*peer.Peer) (n
return nil
}
+func (m *Manager) removeNeighbor(id peer.ID) (*Neighbor, error) {
+ m.mu.Lock()
+ defer m.mu.Unlock()
+ if _, ok := m.neighbors[id]; !ok {
+ return nil, ErrNotANeighbor
+ }
+ n := m.neighbors[id]
+ delete(m.neighbors, id)
+ return n, nil
+}
+
func (m *Manager) handlePacket(data []byte, p *peer.Peer) error {
// ignore empty packages
if len(data) == 0 {
--
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