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Support dynamically allocated lockdep keys #1102

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fbq opened this issue Aug 16, 2024 · 1 comment
Open

Support dynamically allocated lockdep keys #1102

fbq opened this issue Aug 16, 2024 · 1 comment
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@chessturo
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• lib Related to the `rust/` library. unsound The possibility of UB in safe code.

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@fbq
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fbq commented Aug 16, 2024

Currently, there's a design hole which allows users to pass an unregistered lockdep key to a C function that expects a registered one: example. We can fix this by:

  • Replace &LockClassKey with Pin<&LockClassKey> in all lock APIs to reflect that the lock keys need address stability to work.
  • Introduce pin initializer for LockClassKey, which registers the key at the initialization time.
  • Add pin drop function for LockClassKey, which unregisters the key.
  • Make sure static_lock_class!() still work by creating a Pin<&'static LockClassKey> from a static uninit variable (as long as it's static allocated, lockdep supports the uninitialized key).

Detailed discussions can be found: https://lore.kernel.org/rust-for-linux/2e3bc20e-ca91-45bb-9e35-586620e56d96@proton.me/
@fbq fbq added • lib Related to the `rust/` library. unsound The possibility of UB in safe code. labels Aug 16, 2024
@chessturo
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Looking into getting a patch out for this

@fbq fbq assigned fbq and chessturo and unassigned fbq Aug 16, 2024
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this issue Dec 19, 2024
@chessturo @intel-lab-lkp
rust: lockdep: Use Pin for all LockClassKey usages
2dd9126 
Reintroduce dynamically-allocated LockClassKeys such that they are
automatically (de)registered. Require that all usages of LockClassKeys
ensure that they are Pin'd.

Closes: Rust-for-Linux#1102
Suggested-by: Benno Lossin <benno.lossin@proton.me>
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Mitchell Levy <levymitchell0@gmail.com>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this issue Feb 5, 2025
@chessturo @intel-lab-lkp
rust: lockdep: Use Pin for all LockClassKey usages
f3d9968 
Reintroduce dynamically-allocated LockClassKeys such that they are
automatically (de)registered. Require that all usages of LockClassKeys
ensure that they are Pin'd.

Closes: Rust-for-Linux#1102
Suggested-by: Benno Lossin <benno.lossin@proton.me>
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Mitchell Levy <levymitchell0@gmail.com>
intel-lab-lkp pushed a commit to intel-lab-lkp/linux that referenced this issue Feb 8, 2025
@chessturo @intel-lab-lkp
rust: lockdep: Use Pin for all LockClassKey usages
c0bce68 
Reintroduce dynamically-allocated LockClassKeys such that they are
automatically (de)registered. Require that all usages of LockClassKeys
ensure that they are Pin'd.

Currently, only `'static` LockClassKeys are supported, so Pin is
redundant. However, it is intended that dynamically-allocated
LockClassKeys will eventually be supported, so using Pin from the outset
will make that change simpler.

Closes: Rust-for-Linux#1102
Suggested-by: Benno Lossin <benno.lossin@proton.me>
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Mitchell Levy <levymitchell0@gmail.com>
Darksonn pushed a commit to Darksonn/linux that referenced this issue Feb 10, 2025
@chessturo @fbq
rust: lockdep: Use Pin for all LockClassKey usages
eb12883 
Reintroduce dynamically-allocated LockClassKeys such that they are
automatically (de)registered. Require that all usages of LockClassKeys
ensure that they are Pin'd.

Currently, only `'static` LockClassKeys are supported, so Pin is
redundant. However, it is intended that dynamically-allocated
LockClassKeys will eventually be supported, so using Pin from the outset
will make that change simpler.

Closes: Rust-for-Linux#1102
Suggested-by: Benno Lossin <benno.lossin@proton.me>
Suggested-by: Boqun Feng <boqun.feng@gmail.com>
Signed-off-by: Mitchell Levy <levymitchell0@gmail.com>
Reviewed-by: Benno Lossin <benno.lossin@proton.me>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Link: https://lore.kernel.org/r/20250207-rust-lockdep-v4-2-7a50a7e88656@gmail.com
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