OpenCloudOS-Kernel/rust/kernel/sync
Alice Ryhl 6fcd6feaf1 rust: sync: require `T: Sync` for `LockedBy::access`
commit a8ee30f45d5d57467ddb7877ed6914d0eba0af7f upstream.

The `LockedBy::access` method only requires a shared reference to the
owner, so if we have shared access to the `LockedBy` from several
threads at once, then two threads could call `access` in parallel and
both obtain a shared reference to the inner value. Thus, require that
`T: Sync` when calling the `access` method.

An alternative is to require `T: Sync` in the `impl Sync for LockedBy`.
This patch does not choose that approach as it gives up the ability to
use `LockedBy` with `!Sync` types, which is okay as long as you only use
`access_mut`.

Cc: stable@vger.kernel.org
Fixes: 7b1f55e3a9 ("rust: sync: introduce `LockedBy`")
Signed-off-by: Alice Ryhl <aliceryhl@google.com>
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://lore.kernel.org/r/20240915-locked-by-sync-fix-v2-1-1a8d89710392@google.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-10-10 11:57:44 +02:00
..
arc rust: sync: arc: Implement Arc<dyn Any + Send + Sync>::downcast() 2023-04-10 23:55:43 +02:00
lock rust: sync: make doctests compilable/testable 2023-07-19 09:32:41 -06:00
arc.rs rust: arc: add explicit `drop()` around `Box::from_raw()` 2024-02-16 19:10:43 +01:00
condvar.rs rust: sync: introduce `CondVar` 2023-04-22 01:46:45 +02:00
lock.rs rust: lock: Add intra-doc links to the Backend trait 2023-08-07 11:33:33 +02:00
locked_by.rs rust: sync: require `T: Sync` for `LockedBy::access` 2024-10-10 11:57:44 +02:00