From 51c4d1851b1e65fc6fcc8a71dd5fc99f51e09a83 Mon Sep 17 00:00:00 2001
From: Jason Woods <devel@jasonwoods.me.uk>
Date: Tue, 23 Nov 2021 11:28:27 +0000
Subject: [PATCH] Fix high CPU reload deadlock in publisher

---
 CHANGELOG.md                           | 1 +
 lc-lib/internallist/list.go            | 8 ++++++++
 lc-lib/publisher/endpoint/sink_list.go | 4 ++--
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 343daf519..1ae985230 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@ Log Courier / Log Carver
 
 - Fixed crash during configuration reload for `tcp` receiver and transport
 - Fixed reload of configuration not correctly updating endpoints
+- Fixed reload of configuration sometimes causing a deadlock with hugh CPU
 
 ## 2.8.0
 
diff --git a/lc-lib/internallist/list.go b/lc-lib/internallist/list.go
index 723186291..3832cb440 100644
--- a/lc-lib/internallist/list.go
+++ b/lc-lib/internallist/list.go
@@ -129,13 +129,21 @@ func (l *List) Remove(e *Element) interface{} {
 }
 
 // PushFront inserts a new element e at the front of list l and returns e.
+// Does nothing and returns e if the item is already in a list.
 func (l *List) PushFront(e *Element) *Element {
+	if e.list != nil {
+		return e
+	}
 	l.lazyInit()
 	return l.insert(e, &l.root)
 }
 
 // PushBack inserts a new element e at the back of list l and returns e.
+// Does nothing and returns e if the item is already in a list.
 func (l *List) PushBack(e *Element) *Element {
+	if e.list != nil {
+		return e
+	}
 	l.lazyInit()
 	return l.insert(e, l.root.prev)
 }
diff --git a/lc-lib/publisher/endpoint/sink_list.go b/lc-lib/publisher/endpoint/sink_list.go
index 71ec51376..7f138570c 100644
--- a/lc-lib/publisher/endpoint/sink_list.go
+++ b/lc-lib/publisher/endpoint/sink_list.go
@@ -83,7 +83,7 @@ func (s *Sink) AddEndpointAfter(server string, addressPool *addresspool.Pool, af
 	if after == nil {
 		s.orderedList.PushFront(&endpoint.orderedElement)
 	} else {
-		s.orderedList.MoveAfter(&endpoint.orderedElement, &after.orderedElement)
+		s.orderedList.InsertAfter(&endpoint.orderedElement, &after.orderedElement)
 	}
 	if s.api != nil {
 		s.api.AddEntry(server, endpoint.apiEntry())
@@ -107,7 +107,7 @@ func (s *Sink) FindEndpoint(server string) *Endpoint {
 func (s *Sink) MoveEndpointAfter(endpoint *Endpoint, after *Endpoint) {
 	if after == nil {
 		s.mutex.Lock()
-		s.orderedList.PushFront(&endpoint.orderedElement)
+		s.orderedList.MoveToFront(&endpoint.orderedElement)
 		s.mutex.Unlock()
 		return
 	}