From 68c1a13195b04f9cfcd88288d165a2917fd14e70 Mon Sep 17 00:00:00 2001
From: Neil Alexander <neilalexander@users.noreply.github.com>
Date: Wed, 6 Apr 2022 12:55:37 +0100
Subject: [PATCH] Take map lock

---
 syncapi/notifier/notifier.go | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/syncapi/notifier/notifier.go b/syncapi/notifier/notifier.go
index a06d6bf2e..4e1a3c2a3 100644
--- a/syncapi/notifier/notifier.go
+++ b/syncapi/notifier/notifier.go
@@ -250,6 +250,8 @@ func (n *Notifier) OnNewPresence(
 }
 
 func (n *Notifier) SharedUsers(userID string) (sharedUsers []string) {
+	n.mapLock.RLock()
+	defer n.mapLock.RUnlock()
 	for roomID, users := range n.roomIDToJoinedUsers {
 		if _, ok := users[userID]; ok {
 			sharedUsers = append(sharedUsers, n.JoinedUsers(roomID)...)
@@ -259,6 +261,8 @@ func (n *Notifier) SharedUsers(userID string) (sharedUsers []string) {
 }
 
 func (n *Notifier) IsSharedUser(userA, userB string) bool {
+	n.mapLock.RLock()
+	defer n.mapLock.RUnlock()
 	var okA, okB bool
 	for _, users := range n.roomIDToJoinedUsers {
 		_, okA = users[userA]