Hi Greg,

On Sun, Mar 16, 2025 at 08:15:32AM +0100, gregkh@linuxfoundation.org wrote:

The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 966944f3711665db13e214fef6d02982c49bb972

It's weird because `cherry-pick` works for me:

$ git cherry-pick -x 966944f3711665db13e214fef6d02982c49bb972 Auto-merging rust/kernel/sync.rs [stable-6.6 f5771e91eac3] rust: lockdep: Remove support for dynamically allocated LockClassKeys Author: Mitchell Levy levymitchell0@gmail.com Date: Fri Mar 7 15:27:00 2025 -0800 1 file changed, 4 insertions(+), 6 deletions(-)

my base is 594a1dd5138a ("Linux 6.6.83").

I checked the original commit in Linus' tree, it removes the `impl Default` which doesn't exist in 6.6, however it seems my `cherry-pick` can realise and fix this! Anyway I will send the fixed patch soon.

Regards, Boqun

# <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2025031632-divorcee-duly-868e@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 966944f3711665db13e214fef6d02982c49bb972 Mon Sep 17 00:00:00 2001 From: Mitchell Levy levymitchell0@gmail.com Date: Fri, 7 Mar 2025 15:27:00 -0800 Subject: [PATCH] rust: lockdep: Remove support for dynamically allocated LockClassKeys

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

Fixes: 6ea5aa08857a ("rust: sync: introduce `LockClassKey`") Suggested-by: Alice Ryhl aliceryhl@google.com Signed-off-by: Mitchell Levy levymitchell0@gmail.com Signed-off-by: Boqun Feng boqun.feng@gmail.com Signed-off-by: Ingo Molnar mingo@kernel.org Reviewed-by: Benno Lossin benno.lossin@proton.me Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20250307232717.1759087-11-boqun.feng@gmail.com

diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs index 3498fb344dc9..16eab9138b2b 100644 --- a/rust/kernel/sync.rs +++ b/rust/kernel/sync.rs @@ -30,28 +30,20 @@ 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();
  

•    static CLASS: $crate::sync::LockClassKey =
  

•        // SAFETY: lockdep expects uninitialized memory when it's handed a statically allocated
  

•        // lock_class_key
  

•        unsafe { ::core::mem::MaybeUninit::uninit().assume_init() };
     &CLASS
  

  }};

}

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.

Fixes: 6ea5aa08857a ("rust: sync: introduce `LockClassKey`") Suggested-by: Alice Ryhl aliceryhl@google.com Signed-off-by: Mitchell Levy levymitchell0@gmail.com Signed-off-by: Boqun Feng boqun.feng@gmail.com Signed-off-by: Ingo Molnar mingo@kernel.org Reviewed-by: Benno Lossin benno.lossin@proton.me Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20250307232717.1759087-11-boqun.feng@gmail.com (cherry picked from commit 966944f3711665db13e214fef6d02982c49bb972) Signed-off-by: Boqun Feng boqun.feng@gmail.com --- rust/kernel/sync.rs | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/rust/kernel/sync.rs b/rust/kernel/sync.rs index d219ee518eff..8b40589b1028 100644 --- a/rust/kernel/sync.rs +++ b/rust/kernel/sync.rs @@ -26,11 +26,6 @@ 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() } @@ -41,7 +36,10 @@ pub(crate) fn as_ptr(&self) -> *mut bindings::lock_class_key { #[macro_export] macro_rules! static_lock_class { () => {{ - static CLASS: $crate::sync::LockClassKey = $crate::sync::LockClassKey::new(); + static CLASS: $crate::sync::LockClassKey = + // SAFETY: lockdep expects uninitialized memory when it's handed a statically allocated + // lock_class_key + unsafe { ::core::mem::MaybeUninit::uninit().assume_init() }; &CLASS }}; }