[PATCH 1/2] rust: lockdep: Remove support for dynamically allocated LockClassKeys

Mitchell Levy via B4 Relay
2024-10-04T22:02:00Z

From: Mitchell Levy <levymitchell0@gmail.com>

Currently, dynamically allocated LockCLassKeys can be used from the Rust
side without having them registered. This is a soundness issue, so
remove them.

Suggested-by: Alice Ryhl <aliceryhl@google.com>
Link: https://lore.kernel.org/rust-for-linux/20240815074519.2684107-3-nmi@metaspace.dk/
Cc: stable@vger.kernel.org
Signed-off-by: Mitchell Levy <levymitchell0@gmail.com>
---
rust/kernel/lib.rs | 2 +-
rust/kernel/sync.rs | 14 ++------------
2 files changed, 3 insertions(+), 13 deletions(-)

diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 22a3bfa5a9e9..b5f4b3ce6b48 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -44,8 +44,8 @@
pub mod page;
pub mod prelude;
pub mod print;
-pub mod sizes;
pub mod rbtree;
+pub mod sizes;
mod static_assert;
#[doc(hidden)]
pub mod std_vendor;
diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs
index 0ab20975a3b5..d270db9b9894 100644
--- a/rust/kernel/sync.rs
+++ b/rust/kernel/sync.rs
@@ -27,28 +27,18 @@
unsafe impl Sync for LockClassKey {}

impl LockClassKey {
- /// Creates a new lock class key.
- pub const fn new() -> Self {
- Self(Opaque::uninit())
- }
-
pub(crate) fn as_ptr(&self) -> *mut bindings::lock_class_key {
self.0.get()
}
}

-impl Default for LockClassKey {
- fn default() -> Self {
- Self::new()
- }
-}
-
/// Defines a new static lock class and returns a pointer to it.
#[doc(hidden)]
#[macro_export]
macro_rules! static_lock_class {
() => {{
- static CLASS: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new();
+ static CLASS: $crate::sync::LockClassKey =
+ unsafe { ::core::mem::MaybeUninit::uninit().assume_init() };
&CLASS
}};
}

--
2.34.1