From c5aefce2ef442dd3571b9e76eb45bada7e7c1b4e Mon Sep 17 00:00:00 2001
From: Sebastian Burckhardt <sburckha@microsoft.com>
Date: Tue, 24 Jan 2023 13:29:57 -0800
Subject: [PATCH] fix race on index data structure caused by locking wrong
 object (#219)

---
 src/DurableTask.Netherite/PartitionState/StatsState.cs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/DurableTask.Netherite/PartitionState/StatsState.cs b/src/DurableTask.Netherite/PartitionState/StatsState.cs
index 995c09c..87a2315 100644
--- a/src/DurableTask.Netherite/PartitionState/StatsState.cs
+++ b/src/DurableTask.Netherite/PartitionState/StatsState.cs
@@ -85,7 +85,7 @@ namespace DurableTask.Netherite
 
             if (this.InstanceIds != null)
             {
-                lock (this)
+                lock (this.InstanceIds)
                 {
                     if (!evt.DeleteInstance)
                     {
@@ -105,7 +105,7 @@ namespace DurableTask.Netherite
 
             if (this.InstanceIds != null)
             {
-                lock (this)
+                lock (this.InstanceIds)
                 {
                     foreach (var key in evt.Purged)
                     {