From a7a79f28a8fe288ec92593835583160f455707ad Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tomasz=20Mi=C4=85sko?= <tomaszmiasko@gmail.com>
Date: Thu, 9 Jan 2020 21:06:11 +0100
Subject: rt: use release ordering in `drop_join_handle_fast` (#2044)

Previously acquire operations reading a value written by a successful
CAS in `drop_join_handle_fast` did not synchronize with it. The CAS
wasn't guaranteed to happen before the task deallocation, and so
created a data race between the two.

Use release success ordering to ensure synchronization.
---
 tokio/src/task/state.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'tokio/src/task')

diff --git a/tokio/src/task/state.rs b/tokio/src/task/state.rs
index dadfe540..b764167e 100644
--- a/tokio/src/task/state.rs
+++ b/tokio/src/task/state.rs
@@ -266,7 +266,7 @@ impl State {
             .compare_exchange_weak(
                 INITIAL_STATE | JOIN_INTEREST,
                 INITIAL_STATE,
-                Relaxed,
+                Release,
                 Relaxed,
             )
             .is_ok()
-- 
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