Gary Guo 10049f274b rust: pin-init: fix incorrect accessor reference lifetime ...

commit 68bf102226 upstream

When a field has been initialized, `init!`/`pin_init!` create a reference
or pinned reference to the field so it can be accessed later during the
initialization of other fields. However, the reference it created is
incorrectly `&'static` rather than just the scope of the initializer.

This means that you can do

    init!(Foo {
        a: 1,
        _: {
            let b: &'static u32 = a;
        }
    })

which is unsound.

This is caused by `&mut (*$slot).$ident`, which actually allows arbitrary
lifetime, so this is effectively `'static`.

Fix it by adding `let_binding` method on `DropGuard` to shorten lifetime.
This results in exactly what we want for these accessors. The safety and
invariant comments of `DropGuard` have been reworked; instead of reasoning
about what caller can do with the guard, express it in a way that the
ownership is transferred to the guard and `forget` takes it back, so the
unsafe operations within the `DropGuard` can be more easily justified.

Assisted-by: Claude:claude-3-opus
Signed-off-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2026-05-17 17:14:34 +02:00

..

__internal.rs

rust: pin-init: fix incorrect accessor reference lifetime

2026-05-17 17:14:34 +02:00

macros.rs

rust: pin-init: fix incorrect accessor reference lifetime

2026-05-17 17:14:34 +02:00