From 6aaef97158c45f75fa1d1136b26e76ff294cd107 Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Mon, 19 Feb 2018 16:48:03 -0500
Subject: [PATCH] Breaks Mac machine shutdown deadlock.

---
 OSBindings/Mac/Clock Signal/Updater/CSBestEffortUpdater.mm | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/OSBindings/Mac/Clock Signal/Updater/CSBestEffortUpdater.mm b/OSBindings/Mac/Clock Signal/Updater/CSBestEffortUpdater.mm
index fdcb9dc9f..80c82bd1f 100644
--- a/OSBindings/Mac/Clock Signal/Updater/CSBestEffortUpdater.mm	
+++ b/OSBindings/Mac/Clock Signal/Updater/CSBestEffortUpdater.mm	
@@ -16,8 +16,10 @@ struct UpdaterDelegate: public Concurrency::BestEffortUpdater::Delegate {
 
 	void update(Concurrency::BestEffortUpdater *updater, int cycles, bool did_skip_previous_update) {
 		[delegateLock lock];
-		[delegate bestEffortUpdater:nil runForCycles:(NSUInteger)cycles didSkipPreviousUpdate:did_skip_previous_update];
+		__weak id<CSBestEffortUpdaterDelegate> delegateCopy = delegate;
 		[delegateLock unlock];
+
+		[delegateCopy bestEffortUpdater:nil runForCycles:(NSUInteger)cycles didSkipPreviousUpdate:did_skip_previous_update];
 	}
 };