From 2d49b0795eaed17c63972cc3d75e633d3e33724c Mon Sep 17 00:00:00 2001
From: "Brian J. Cardiff" <bcardiff@gmail.com>
Date: Wed, 8 Feb 2023 09:19:02 -0300
Subject: [PATCH] Add memory barriers on lock/unlock of SpinLock (#13050)

---
 src/crystal/spin_lock.cr | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/crystal/spin_lock.cr b/src/crystal/spin_lock.cr
index f0b4b2df4ab6..e3136cdf3fe9 100644
--- a/src/crystal/spin_lock.cr
+++ b/src/crystal/spin_lock.cr
@@ -11,11 +11,17 @@ class Crystal::SpinLock
           Intrinsics.pause
         end
       end
+      {% if flag?(:aarch64) %}
+        Atomic::Ops.fence :sequentially_consistent, false 
+      {% end %}      
     {% end %}
   end
 
   def unlock
     {% if flag?(:preview_mt) %}
+      {% if flag?(:aarch64) %}
+        Atomic::Ops.fence :sequentially_consistent, false 
+      {% end %}
       @m.lazy_set(0)
     {% end %}
   end