From 937d13b8efc43f3f2e93f81360565d82f243ce15 Mon Sep 17 00:00:00 2001
From: Slanterns <slanterns.w@gmail.com>
Date: Wed, 16 Oct 2024 00:22:05 +0800
Subject: [PATCH] relax a memory order in `once_box`

---
 library/std/src/sys/sync/once_box.rs | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/library/std/src/sys/sync/once_box.rs b/library/std/src/sys/sync/once_box.rs
index 1422b5a1721..9d24db2245a 100644
--- a/library/std/src/sys/sync/once_box.rs
+++ b/library/std/src/sys/sync/once_box.rs
@@ -8,7 +8,7 @@
 use crate::mem::replace;
 use crate::ptr::null_mut;
 use crate::sync::atomic::AtomicPtr;
-use crate::sync::atomic::Ordering::{AcqRel, Acquire, Relaxed};
+use crate::sync::atomic::Ordering::{Acquire, Relaxed, Release};
 
 pub(crate) struct OnceBox<T> {
     ptr: AtomicPtr<T>,
@@ -60,7 +60,7 @@ pub fn take(&mut self) -> Option<Box<T>> {
     #[cold]
     fn initialize(&self, f: impl FnOnce() -> Box<T>) -> &T {
         let new_ptr = Box::into_raw(f());
-        match self.ptr.compare_exchange(null_mut(), new_ptr, AcqRel, Acquire) {
+        match self.ptr.compare_exchange(null_mut(), new_ptr, Release, Acquire) {
             Ok(_) => unsafe { &*new_ptr },
             Err(ptr) => {
                 // Lost the race to another thread.