From baf98accd0bae8248e201e915d985fffcbe5ad90 Mon Sep 17 00:00:00 2001
From: Ravi Khadiwala <ravi@signal.org>
Date: Tue, 25 Jul 2023 15:05:00 -0500
Subject: [PATCH] acquire lock before checking message listeners in
 MessagesCache

---
 .../whispersystems/textsecuregcm/storage/MessagesCache.java  | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/storage/MessagesCache.java b/service/src/main/java/org/whispersystems/textsecuregcm/storage/MessagesCache.java
index c3c095061..52e04b858 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/storage/MessagesCache.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/storage/MessagesCache.java
@@ -388,7 +388,10 @@ public class MessagesCache extends RedisClusterPubSubAdapter<String, String> imp
   }
 
   public void removeMessageAvailabilityListener(final MessageAvailabilityListener listener) {
-    @Nullable final String queueName = queueNamesByMessageListener.get(listener);
+    @Nullable final String queueName;
+    synchronized (messageListenersByQueueName) {
+      queueName = queueNamesByMessageListener.get(listener);
+    }
 
     if (queueName != null) {
       unsubscribeFromKeyspaceNotifications(queueName);