From 64e9f6797ad8c38c1c44c15a1e75135296a1e966 Mon Sep 17 00:00:00 2001
From: Daniel Micay <danielmicay@gmail.com>
Date: Tue, 16 Oct 2018 15:52:41 -0400
Subject: [PATCH] use offsetof for allocator_state memory protection

---
 malloc.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/malloc.c b/malloc.c
index 5ba8b8b..2629e8c 100644
--- a/malloc.c
+++ b/malloc.c
@@ -777,8 +777,7 @@ COLD static void init_slow_path(void) {
     if (allocator_state == NULL) {
         fatal_error("failed to reserve allocator state");
     }
-    if (memory_protect_rw(allocator_state, sizeof(allocator_state->size_class_metadata) +
-        sizeof(allocator_state->region_allocator))) {
+    if (memory_protect_rw(allocator_state, offsetof(struct allocator_state, regions_a))) {
         fatal_error("failed to unprotect allocator state");
     }