From 4827fd71b4fbaec9df9529a468d815eee306a12a Mon Sep 17 00:00:00 2001
From: Michael Scire <SciresM@gmail.com>
Date: Fri, 7 Dec 2018 14:27:46 -0800
Subject: [PATCH] fusee: Fix race condition involving volatile reads

---
 fusee/fusee-secondary/src/smmu.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fusee/fusee-secondary/src/smmu.c b/fusee/fusee-secondary/src/smmu.c
index 23bd3d37d..db54e5d9d 100644
--- a/fusee/fusee-secondary/src/smmu.c
+++ b/fusee/fusee-secondary/src/smmu.c
@@ -226,9 +226,10 @@ void smmu_emulate_tsec(void *tsec_keys, const void *package1, size_t package1_si
     uint32_t old_key_data = *key_data;
     uint32_t buf_counter = 0;
     while (!(tsec->FALCON_CPUCTL & 0x10)) {
-        if (*key_data != old_key_data) {
-            old_key_data = *key_data;
-            key_buf[buf_counter] = *key_data;
+        const uint32_t new_key_data = *key_data;
+        if (new_key_data != old_key_data) {
+            old_key_data = new_key_data;
+            key_buf[buf_counter] = new_key_data;
             buf_counter++;
         }
     }