From 4bcafe89c48f6618ced290e14b3186d9b1e8006e Mon Sep 17 00:00:00 2001
From: Stephen Gutekanst <stephen@hexops.com>
Date: Sat, 30 Nov 2024 12:00:45 -0700
Subject: [PATCH] object: fix race detected by tsan in mpsc queue

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
---
 src/mpsc.zig | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/mpsc.zig b/src/mpsc.zig
index a1bd2634..c6eb7c57 100644
--- a/src/mpsc.zig
+++ b/src/mpsc.zig
@@ -350,6 +350,15 @@ pub fn Queue(comptime Value: type) type {
                     // Lost race (with another takeAll() or pop()), retry from start
                     continue :outer;
                 }
+
+                // Ensure all previous atomic operations (including linking) are complete
+                // Specifically this part of pushRaw():
+                //
+                // // Link previous node to new node
+                // @atomicStore(?*Node, &prev.next, node, .release);
+                //
+                _ = @atomicLoad(*Node, &q.head, .acquire);
+
                 return tail;
             }
         }