From 705c641428be9862699bead26e0b2d2dca273782 Mon Sep 17 00:00:00 2001
From: Ollie <zjac281@live.rhul.ac.uk>
Date: Thu, 13 Aug 2026 09:06:24 +0100
Subject: [PATCH] fix: correct synchronisation when dropping Arc and Weak

---
 stabby-abi/src/alloc/sync.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/stabby-abi/src/alloc/sync.rs b/stabby-abi/src/alloc/sync.rs
index af20e54..8a6a168 100644
--- a/stabby-abi/src/alloc/sync.rs
+++ b/stabby-abi/src/alloc/sync.rs
@@ -304,11 +304,12 @@ impl<T, Alloc: IAlloc> Drop for Arc<T, Alloc> {
     fn drop(&mut self) {
         if unsafe { self.ptr.prefix() }
             .strong
-            .fetch_sub(1, Ordering::Relaxed)
+            .fetch_sub(1, Ordering::Release)
             != 1
         {
             return;
         }
+        core::sync::atomic::fence(Ordering::Acquire);
         unsafe {
             core::ptr::drop_in_place(self.ptr.as_mut());
             _ = Weak::<T, Alloc>::from_raw(self.ptr);
@@ -401,11 +402,12 @@ impl<T, Alloc: IAlloc> Drop for Weak<T, Alloc> {
     fn drop(&mut self) {
         if unsafe { self.ptr.prefix() }
             .weak
-            .fetch_sub(1, Ordering::Relaxed)
+            .fetch_sub(1, Ordering::Release)
             != 1
         {
             return;
         }
+        core::sync::atomic::fence(Ordering::Acquire);
         unsafe {
             let mut alloc = self.ptr.prefix().alloc.assume_init_read();
             self.ptr.free(&mut alloc)