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/sync.rs | 16 ++++------------
1 file changed, 4 insertions(+), 12 deletions(-)
diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs
index 1eab7ebf25fd..ae16bfd98de2 100644
--- a/rust/kernel/sync.rs
+++ b/rust/kernel/sync.rs
@@ -29,28 +29,20 @@
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();
+ // SAFETY: lockdep expects uninitialized memory when it's handed a statically allocated
+ // lock_class_key
+ static CLASS: $crate::sync::LockClassKey =
+ unsafe { ::core::mem::MaybeUninit::uninit().assume_init() };
&CLASS
}};
}
--
2.34.1On Thu, Dec 19, 2024 at 12:58:55PM -0800, Mitchell Levy wrote:
> 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/sync.rs | 16 ++++------------
> 1 file changed, 4 insertions(+), 12 deletions(-)
>
> diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs
> index 1eab7ebf25fd..ae16bfd98de2 100644
> --- a/rust/kernel/sync.rs
> +++ b/rust/kernel/sync.rs
> @@ -29,28 +29,20 @@
> 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();
> + // SAFETY: lockdep expects uninitialized memory when it's handed a statically allocated
> + // lock_class_key
> + static CLASS: $crate::sync::LockClassKey =
About the clippy warning reported by 0day, I think you could resolve
that by moving the above safety comment here.
Regards,
Boqun
> + unsafe { ::core::mem::MaybeUninit::uninit().assume_init() };
> &CLASS
> }};
> }
>
> --
> 2.34.1
>
Hi Mitchell,
kernel test robot noticed the following build warnings:
[auto build test WARNING on 0c5928deada15a8d075516e6e0d9ee19011bb000]
url: https://github.com/intel-lab-lkp/linux/commits/Mitchell-Levy/rust-lockdep-Remove-support-for-dynamically-allocated-LockClassKeys/20241220-050220
base: 0c5928deada15a8d075516e6e0d9ee19011bb000
patch link: https://lore.kernel.org/r/20241219-rust-lockdep-v2-1-f65308fbc5ca%40gmail.com
patch subject: [PATCH v2 1/2] rust: lockdep: Remove support for dynamically allocated LockClassKeys
config: x86_64-rhel-9.4-rust (https://download.01.org/0day-ci/archive/20241225/202412251433.T3BhO2CQ-lkp@intel.com/config)
compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project ab51eccf88f5321e7c60591c5546b254b6afab99)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241225/202412251433.T3BhO2CQ-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202412251433.T3BhO2CQ-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> warning: unsafe block missing a safety comment
--> rust/kernel/sync.rs:45:13
|
45 | unsafe { ::core::mem::MaybeUninit::uninit().assume_init() };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
::: rust/kernel/block/mq/gen_disk.rs:111:17
|
111 | static_lock_class!().as_ptr(),
| -------------------- in this macro invocation
|
= help: consider adding a safety comment on the preceding line
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#undocumented_unsafe_blocks
= note: requested on the command line with `-W clippy::undocumented-unsafe-blocks`
= note: this warning originates in the macro `static_lock_class` (in Nightly builds, run with -Z macro-backtrace for more info)
--
>> warning: unsafe block missing a safety comment
--> rust/kernel/sync.rs:45:13
|
45 | unsafe { ::core::mem::MaybeUninit::uninit().assume_init() };
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
::: rust/kernel/workqueue.rs:218:21
|
218 | work <- new_work!("Queue::try_spawn"),
| ----------------------------- in this macro invocation
|
= help: consider adding a safety comment on the preceding line
= help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#undocumented_unsafe_blocks
= note: this warning originates in the macro `$crate::static_lock_class` which comes from the expansion of the macro `new_work` (in Nightly builds, run with -Z macro-backtrace for more info)
--
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