linux.git/rust/kernel/sync.rs, branch v7.3-rc2

Merge tag 'rcu.2026.08.18a' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux

2026-08-24T01:00:22+00:00

Pull RCU updates from Paul McKenney:
 "Make expedited grace periods expedite normal RCU callbacks

  Miscellaneous fixes:
   - Improve diagnostic output with character task states
   - Mark accesses to inform KCSAN of concurrency design
   - Move from kmalloc() to kmalloc_obj()
   - Documentation updates
   - Improve handling of RCU deferred quiescent states
   - Clean up unused function arguments and structure fields
   - Reduce show_rcu_gp_kthreads() stack space

  Tasks RCU updates:
   - Clean up after SRCU re-implementation of Tasks Trace RCU
   - Mark accesses to inform KCSAN of concurrency design
   - Add ->lazy_timer status to diagnostic output
   - Remove an unnecessary memory barrier
   - Fix a data race, courtesy of KCSAN
   - Documentation updates
   - Convert cond_resched_tasks_rcu_qs() from macro to static inline
     function

  SRCU updates:
   - Add Rust helpers for SRCU
   - Avoid losing queued work at cleanup_srcu_struct() time

  Torture-test updates:
   - Preparation work for immediate RCU priority deboosting
   - Test RCU readers from real interrupt handlers (as opposed to
     softirq)
   - Simplify code through use of cpumask_next_wrap()
   - Improve diagnostic output with character task states
   - Add rcutorture.nwriters parameter to allow lightweight stall
     testing, and rcutorture.stall_only to make doing so easier
   - Test an RCU Tasks Trace grace period implying an RCU grace period
   - Make RCU Tasks Trace torturing track reader batches
   - Fix a data race, courtesy of KCSAN
   - Plug a shuffle_tmp_mask memory leak on kthread spawn failure"

* tag 'rcu.2026.08.18a' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux: (59 commits)
  rcu: Add closing parenthesis in comment in rcu_read_unlock_strict()
  rcutorture: Make {,s}rcu_read_delay() better handle forward-progress testing
  rcutorture: Announce declining to forward-progress test
  torture: Don't leak shuffle_tmp_mask when shuffler kthread fails to start
  rcutorture: Use this_cpu_inc() for rcu_torture_count[] and rcu_torture_batch[]
  rcutorture: Make RCU Tasks Trace track Reader Batches
  rcutorture: Test RCU Tasks Trace GP implying RCU GP
  rcutorture: Add a stall_only module parameter
  rcutorture: Add nwriters module parameter
  rcutorture: Use task_state_to_char() for task-state reporting
  rcutorture: Use cpumask_next_wrap() in rcu_torture_preempt()
  rcutorture: Test RCU readers from hardware interrupt handlers
  rcutorture: Check for immediate deboosting at reader end
  srcu: Queue sdp->work when the delay timer is successfully deleted
  rcu-tasks: Convert cond_resched_tasks_rcu_qs() to static inline
  rcu-tasks: Fix some comments for call_rcu_tasks() and call_rcu_tasks_rude()
  rcu-tasks: Rename tasks_rcu_exit_srcu_stall_timer to tasks_rcu_exit_stall_timer
  rcu: Mark interrupts-enabled accesses to rdp->cpu_no_qs.s
  rcu: Reduce stack usage in show_rcu_gp_kthreads()
  rcu: Mark accesses to ->rcu_urgent_qs and ->rcu_need_heavy_qs
  ...

rust: sync: Add SpinLockIrq

2026-08-10T10:53:10+00:00

A variant of `SpinLock` that ensures interrupts are disabled in the
critical section. `lock()` will ensure that either interrupts are
already disabled or disable them. `unlock()` will reverse the respective
operation.

[Boqun: Port to use spin_lock_irq_disable() and
spin_unlock_irq_enable()]

Signed-off-by: Lyude Paul 
Signed-off-by: Boqun Feng 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Gary Guo 
Link: https://patch.msgid.link/20260807070218.27144-18-boqun@kernel.org

rust: sync: add SRCU abstraction

2026-07-15T22:34:26+00:00

Add a Rust abstraction for sleepable RCU (SRCU), backed by C srcu_struct.
Provide FFI helpers and a safe wrapper with a guard-based API for read-side
critical sections.

Cleanup is handled via `PinnedDrop`. It first checks for active read-side
sections and emits a warning if any guards were leaked. In that case, it
waits in `synchronize_srcu()` rather than risking a UAF by freeing the
`srcu_struct` that is still reachable from the C side. It then uses
`srcu_barrier()` to drain pending callbacks before finally calling
`cleanup_srcu_struct()`.

Signed-off-by: Onur Özkan 
Reviewed-by: Gary Guo 
Reviewed-by: Alice Ryhl 
Reviewed-by: Boqun Feng 
Signed-off-by: Paul E. McKenney

rust: sync: Replace `kernel::c_str!` with C-Strings

2026-01-28T08:25:44+00:00

C-String literals were added in Rust 1.77. Replace instances of
`kernel::c_str!` with C-String literals where possible.

Signed-off-by: Tamir Duberstein 
Signed-off-by: Boqun Feng 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Gary Guo 
Link: https://patch.msgid.link/20260120-cstr-sync-again-v1-1-2a775a2a36fd@kernel.org
Link: https://patch.msgid.link/20260123054624.8226-2-boqun.feng@gmail.com

rust: sync: Clean up LockClassKey and its docs

2026-01-09T11:01:40+00:00

Several aspects of the code and documentation for this type is
incomplete. Also several things are hidden from the docs. Thus, clean it
up and make it easier to read the rendered html docs.

Reviewed-by: Daniel Almeida 
Signed-off-by: Alice Ryhl 
Reviewed-by: Benno Lossin 
Signed-off-by: Boqun Feng 
Link: https://patch.msgid.link/20250811-lock-class-key-cleanup-v3-2-b12967ee1ca2@google.com

rust: sync: Refactor static_lock_class!() macro

2026-01-09T11:01:40+00:00

By introducing a new_static() constructor, the macro does not need to go
through MaybeUninit::uninit().assume_init(), which is a pattern that is
best avoided when possible.

The safety comment not only requires that the value is leaked, but also
that it is stored in the right portion of memory. This is so that the
lockdep static_obj() check will succeed when using this constructor. One
could argue that lockdep detects this scenario, so that safety
requirement isn't needed. However, it simplifies matters to require that
static_obj() will succeed and it's not a burdensome requirement on the
caller.

Suggested-by: Benno Lossin 
Reviewed-by: Daniel Almeida 
Reviewed-by: Benno Lossin 
Signed-off-by: Alice Ryhl 
Signed-off-by: Boqun Feng 
Link: https://patch.msgid.link/20250811-lock-class-key-cleanup-v3-1-b12967ee1ca2@google.com

Merge tag 'modules-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux

2025-12-06T16:27:07+00:00

Pull module updates from Daniel Gomez:
 "Rust module parameter support:

   - Add Rust module parameter support, enabling Rust kernel modules to
     declare and use module parameters. The rust_minimal sample module
     demonstrates this, and the rust null block driver will be the first
     to use it in the next cycle. This also adds the Rust module files
     under the modules subsystem as agreed between the Rust and modules
     maintainers.

  Hardening:

   - Add compile-time check for embedded NUL characters in MODULE_*()
     macros. This module metadata was once used (and maybe still) to
     bypass license enforcement (LWN article from 2003):

	https://lwn.net/Articles/82305/ [1]

  MAINTAINERS:

   - Add Aaron Tomlin as reviewer for the Modules subsystem"

* tag 'modules-6.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/modules/linux:
  MAINTAINERS: Add myself as reviewer for module support
  module: Add compile-time check for embedded NUL characters
  media: radio: si470x: Fix DRIVER_AUTHOR macro definition
  media: dvb-usb-v2: lmedm04: Fix firmware macro definitions
  modules: add rust modules files to MAINTAINERS
  rust: samples: add a module parameter to the rust_minimal sample
  rust: module: update the module macro with module parameter support
  rust: module: use a reference in macros::module::module
  rust: introduce module_param module
  rust: str: add radix prefixed integer parsing functions
  rust: sync: add `SetOnce`

rust: sync: replace `kernel::c_str!` with C-Strings

2025-11-19T21:41:12+00:00

C-String literals were added in Rust 1.77. Replace instances of
`kernel::c_str!` with C-String literals where possible.

Acked-by: Greg Kroah-Hartman 
Reviewed-by: Alice Ryhl 
Reviewed-by: Benno Lossin 
Signed-off-by: Tamir Duberstein 
Link: https://patch.msgid.link/20251117-core-cstr-cstrings-v4-1-924886ad9f75@gmail.com
Signed-off-by: Miguel Ojeda

rust: sync: add `SetOnce`

2025-11-03T13:40:35+00:00

Introduce the `SetOnce` type, a container that can only be written once.
The container uses an internal atomic to synchronize writes to the internal
value.

Reviewed-by: Alice Ryhl 
Reviewed-by: Benno Lossin 
Signed-off-by: Andreas Hindborg 
Tested-by: Daniel Gomez 
Signed-off-by: Daniel Gomez

rust: implement `kernel::sync::Refcount`

2025-09-15T07:38:35+00:00

This is a wrapping layer of `include/linux/refcount.h`. Currently the
kernel refcount has already been used in `Arc`, however it calls into
FFI directly.

[boqun: Add the missing <> for the link in comment]
Signed-off-by: Gary Guo 
Signed-off-by: Boqun Feng 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Alice Ryhl 
Reviewed-by: Boqun Feng 
Reviewed-by: Fiona Behrens 
Reviewed-by: Benno Lossin 
Reviewed-by: Elle Rhumsaa 
Link: https://lore.kernel.org/r/20250723233312.3304339-2-gary@kernel.org