Auto merge of #121646 - ibraheemdev:patch-17, r=ChrisDenton

Fix race between block initialization and receiver disconnection

Port of https://github.com/crossbeam-rs/crossbeam/pull/1084. Closes https://github.com/rust-lang/rust/issues/121582.
This commit is contained in:
bors 2024-02-26 19:46:01 +00:00
commit fc3800f657

View File

@ -547,7 +547,7 @@ fn discard_all_messages(&self) {
}
let mut head = self.head.index.load(Ordering::Acquire);
let mut block = self.head.block.load(Ordering::Acquire);
let mut block = self.head.block.swap(ptr::null_mut(), Ordering::AcqRel);
// If we're going to be dropping messages we need to synchronize with initialization
if head >> SHIFT != tail >> SHIFT {
@ -588,8 +588,8 @@ fn discard_all_messages(&self) {
drop(Box::from_raw(block));
}
}
head &= !MARK_BIT;
self.head.block.store(ptr::null_mut(), Ordering::Release);
self.head.index.store(head, Ordering::Release);
}