Merge pull request #606 from Mortano/union-repr

zeenix · web-flow · commit ceb3fc06baae · 2025-09-08T13:54:41.000Z
Fix memory layout of UnionNode&lt;T&gt; in pool module
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -33,6 +33,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 - CI now uses flags specified in `Cargo.toml` for `rustdoc` tests.
 - Fixed clippy lints.
+- Fixed the memory layout of the internal `UnionNode<T>` type, fixing possible Undefined Behaviour.
 
 ### Removed
 
diff --git a/src/pool/treiber.rs b/src/pool/treiber.rs
@@ -44,6 +44,7 @@ pub trait Node: Sized {
     fn next_mut(&mut self) -> &mut AtomicPtr<Self>;
 }
 
+#[repr(C)]
 pub union UnionNode<T> {
     next: ManuallyDrop<AtomicPtr<UnionNode<T>>>,
     pub data: ManuallyDrop<T>,

Original file line number	Diff line number	Diff line change
`@@ -44,6 +44,7 @@ pub trait Node: Sized {`
`44`	`44`	`fn next_mut(&mut self) -> &mut AtomicPtr<Self>;`
`45`	`45`	`}`
`46`	`46`
	`47`	`+#[repr(C)]`
`47`	`48`	`pub union UnionNode<T> {`
`48`	`49`	`next: ManuallyDrop<AtomicPtr<UnionNode<T>>>,`
`49`	`50`	`pub data: ManuallyDrop<T>,`