Merge tag 'locking-core-2025-01-20' of git://git.kernel.org/pub/scm/l…

…inux/kernel/git/tip/tip

Pull locking updates from Ingo Molnar:
 "Lockdep:

   - Improve and fix lockdep bitsize limits, clarify the Kconfig
     documentation (Carlos Llamas)

   - Fix lockdep build warning on Clang related to
     chain_hlock_class_idx() inlining (Andy Shevchenko)

   - Relax the requirements of PROVE_RAW_LOCK_NESTING arch support by
     not tying it to ARCH_SUPPORTS_RT unnecessarily (Waiman Long)

  Rust integration:

   - Support lock pointers managed by the C side (Lyude Paul)

   - Support guard types (Lyude Paul)

   - Update MAINTAINERS file filters to include the Rust locking code
     (Boqun Feng)

  Wake-queues:

   - Add raw_spin_*wake() helpers to simplify locking code (John Stultz)

  SMP cross-calls:

   - Fix potential data update race by evaluating the local cond_func()
     before IPI side-effects (Mathieu Desnoyers)

  Guard primitives:

   - Ease [c]tags based searches by including the cleanup/guard type
     primitives (Peter Zijlstra)

  ww_mutexes:

   - Simplify the ww_mutex self-test code via swap() (Thorsten Blum)

  Static calls:

   - Update the static calls MAINTAINERS file-pattern (Jiri Slaby)"

* tag 'locking-core-2025-01-20' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  MAINTAINERS: Add static_call_inline.c to STATIC BRANCH/CALL
  cleanup, tags: Create tags for the cleanup primitives
  sched/wake_q: Add helper to call wake_up_q after unlock with preemption disabled
  rust: sync: Add lock::Backend::assert_is_held()
  rust: sync: Add SpinLockGuard type alias
  rust: sync: Add MutexGuard type alias
  rust: sync: Make Guard::new() public
  rust: sync: Add Lock::from_raw() for Lock<(), B>
  locking: MAINTAINERS: Start watching Rust locking primitives
  lockdep: Move lockdep_assert_locked() under #ifdef CONFIG_PROVE_LOCKING
  lockdep: Mark chain_hlock_class_idx() with __maybe_unused
  lockdep: Document MAX_LOCKDEP_CHAIN_HLOCKS calculation
  lockdep: Clarify size for LOCKDEP_*_BITS configs
  lockdep: Fix upper limit for LOCKDEP_*_BITS configs
  locking/ww_mutex/test: Use swap() macro
  smp/scf: Evaluate local cond_func() before IPI side-effects
  locking/lockdep: Enforce PROVE_RAW_LOCK_NESTING only if ARCH_SUPPORTS_RT

MAINTAINERS

@@ -13439,8 +13439,8 @@ LOCKING PRIMITIVES
 M:	Peter Zijlstra <peterz@infradead.org>
 M:	Ingo Molnar <mingo@redhat.com>
 M:	Will Deacon <will@kernel.org>
+M:	Boqun Feng <boqun.feng@gmail.com> (LOCKDEP & RUST)
 R:	Waiman Long <longman@redhat.com>
-R:	Boqun Feng <boqun.feng@gmail.com> (LOCKDEP)
 L:	linux-kernel@vger.kernel.org
 S:	Maintained
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git locking/core
@@ -13454,6 +13454,11 @@ F:	include/linux/seqlock.h
 F:	include/linux/spinlock*.h
 F:	kernel/locking/
 F:	lib/locking*.[ch]
+F:	rust/helpers/mutex.c
+F:	rust/helpers/spinlock.c
+F:	rust/kernel/sync/lock.rs
+F:	rust/kernel/sync/lock/
+F:	rust/kernel/sync/locked_by.rs
 X:	kernel/locking/locktorture.c
 
 LOGICAL DISK MANAGER SUPPORT (LDM, Windows 2000/XP/Vista Dynamic Disks)
@@ -22467,7 +22472,7 @@ F:	arch/*/kernel/static_call.c
 F:	include/linux/jump_label*.h
 F:	include/linux/static_call*.h
 F:	kernel/jump_label.c
-F:	kernel/static_call.c
+F:	kernel/static_call*.c
 
 STI AUDIO (ASoC) DRIVERS
 M:	Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>

include/linux/sched/wake_q.h

@@ -63,4 +63,38 @@ extern void wake_q_add(struct wake_q_head *head, struct task_struct *task);
 extern void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task);
 extern void wake_up_q(struct wake_q_head *head);
 
+/* Spin unlock helpers to unlock and call wake_up_q with preempt disabled */
+static inline
+void raw_spin_unlock_wake(raw_spinlock_t *lock, struct wake_q_head *wake_q)
+{
+	guard(preempt)();
+	raw_spin_unlock(lock);
+	if (wake_q) {
+		wake_up_q(wake_q);
+		wake_q_init(wake_q);
+	}
+}
+
+static inline
+void raw_spin_unlock_irq_wake(raw_spinlock_t *lock, struct wake_q_head *wake_q)
+{
+	guard(preempt)();
+	raw_spin_unlock_irq(lock);
+	if (wake_q) {
+		wake_up_q(wake_q);
+		wake_q_init(wake_q);
+	}
+}
+
+static inline
+void raw_spin_unlock_irqrestore_wake(raw_spinlock_t *lock, unsigned long flags,
+				     struct wake_q_head *wake_q)
+{
+	guard(preempt)();
+	raw_spin_unlock_irqrestore(lock, flags);
+	if (wake_q) {
+		wake_up_q(wake_q);
+		wake_q_init(wake_q);
+	}
+}
 #endif /* _LINUX_SCHED_WAKE_Q_H */

kernel/futex/pi.c

@@ -1020,10 +1020,7 @@ int futex_lock_pi(u32 __user *uaddr, unsigned int flags, ktime_t *time, int tryl
 	 * it sees the futex_q::pi_state.
 	 */
 	ret = __rt_mutex_start_proxy_lock(&q.pi_state->pi_mutex, &rt_waiter, current, &wake_q);
-	preempt_disable();
-	raw_spin_unlock_irq(&q.pi_state->pi_mutex.wait_lock);
-	wake_up_q(&wake_q);
-	preempt_enable();
+	raw_spin_unlock_irq_wake(&q.pi_state->pi_mutex.wait_lock, &wake_q);
 
 	if (ret) {
 		if (ret == 1)

kernel/locking/lockdep.c

@@ -157,10 +157,12 @@ static inline void lockdep_unlock(void)
 	__this_cpu_dec(lockdep_recursion);
 }
 
+#ifdef CONFIG_PROVE_LOCKING
 static inline bool lockdep_assert_locked(void)
 {
 	return DEBUG_LOCKS_WARN_ON(__owner != current);
 }
+#endif
 
 static struct task_struct *lockdep_selftest_task_struct;
 
@@ -430,7 +432,7 @@ static inline u16 hlock_id(struct held_lock *hlock)
 	return (hlock->class_idx | (hlock->read << MAX_LOCKDEP_KEYS_BITS));
 }
 
-static inline unsigned int chain_hlock_class_idx(u16 hlock_id)
+static inline __maybe_unused unsigned int chain_hlock_class_idx(u16 hlock_id)
 {
 	return hlock_id & (MAX_LOCKDEP_KEYS - 1);
 }

kernel/locking/lockdep_internals.h

@@ -119,7 +119,8 @@ static const unsigned long LOCKF_USED_IN_IRQ_READ =
 
 #define MAX_LOCKDEP_CHAINS	(1UL << MAX_LOCKDEP_CHAINS_BITS)
 
-#define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS*5)
+#define AVG_LOCKDEP_CHAIN_DEPTH		5
+#define MAX_LOCKDEP_CHAIN_HLOCKS (MAX_LOCKDEP_CHAINS * AVG_LOCKDEP_CHAIN_DEPTH)
 
 extern struct lock_chain lock_chains[];
 

kernel/locking/mutex.c

@@ -657,10 +657,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
 				goto err;
 		}
 
-		raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
-		/* Make sure we do wakeups before calling schedule */
-		wake_up_q(&wake_q);
-		wake_q_init(&wake_q);
+		raw_spin_unlock_irqrestore_wake(&lock->wait_lock, flags, &wake_q);
 
 		schedule_preempt_disabled();
 
@@ -710,8 +707,7 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
 	if (ww_ctx)
 		ww_mutex_lock_acquired(ww, ww_ctx);
 
-	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
-	wake_up_q(&wake_q);
+	raw_spin_unlock_irqrestore_wake(&lock->wait_lock, flags, &wake_q);
 	preempt_enable();
 	return 0;
 
@@ -720,10 +716,9 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
 	__mutex_remove_waiter(lock, &waiter);
 err_early_kill:
 	trace_contention_end(lock, ret);
-	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+	raw_spin_unlock_irqrestore_wake(&lock->wait_lock, flags, &wake_q);
 	debug_mutex_free_waiter(&waiter);
 	mutex_release(&lock->dep_map, ip);
-	wake_up_q(&wake_q);
 	preempt_enable();
 	return ret;
 }
@@ -935,10 +930,7 @@ static noinline void __sched __mutex_unlock_slowpath(struct mutex *lock, unsigne
 	if (owner & MUTEX_FLAG_HANDOFF)
 		__mutex_handoff(lock, next);
 
-	preempt_disable();
-	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
-	wake_up_q(&wake_q);
-	preempt_enable();
+	raw_spin_unlock_irqrestore_wake(&lock->wait_lock, flags, &wake_q);
 }
 
 #ifndef CONFIG_DEBUG_LOCK_ALLOC

kernel/locking/rtmutex.c

@@ -1292,13 +1292,7 @@ static int __sched task_blocks_on_rt_mutex(struct rt_mutex_base *lock,
 	 */
 	get_task_struct(owner);
 
-	preempt_disable();
-	raw_spin_unlock_irq(&lock->wait_lock);
-	/* wake up any tasks on the wake_q before calling rt_mutex_adjust_prio_chain */
-	wake_up_q(wake_q);
-	wake_q_init(wake_q);
-	preempt_enable();
-
+	raw_spin_unlock_irq_wake(&lock->wait_lock, wake_q);
 
 	res = rt_mutex_adjust_prio_chain(owner, chwalk, lock,
 					 next_lock, waiter, task);
@@ -1642,13 +1636,7 @@ static int __sched rt_mutex_slowlock_block(struct rt_mutex_base *lock,
 			owner = rt_mutex_owner(lock);
 		else
 			owner = NULL;
-		preempt_disable();
-		raw_spin_unlock_irq(&lock->wait_lock);
-		if (wake_q) {
-			wake_up_q(wake_q);
-			wake_q_init(wake_q);
-		}
-		preempt_enable();
+		raw_spin_unlock_irq_wake(&lock->wait_lock, wake_q);
 
 		if (!owner || !rtmutex_spin_on_owner(lock, waiter, owner))
 			rt_mutex_schedule();
@@ -1799,10 +1787,7 @@ static int __sched rt_mutex_slowlock(struct rt_mutex_base *lock,
 	 */
 	raw_spin_lock_irqsave(&lock->wait_lock, flags);
 	ret = __rt_mutex_slowlock_locked(lock, ww_ctx, state, &wake_q);
-	preempt_disable();
-	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
-	wake_up_q(&wake_q);
-	preempt_enable();
+	raw_spin_unlock_irqrestore_wake(&lock->wait_lock, flags, &wake_q);
 	rt_mutex_post_schedule();
 
 	return ret;
@@ -1860,11 +1845,7 @@ static void __sched rtlock_slowlock_locked(struct rt_mutex_base *lock,
 			owner = rt_mutex_owner(lock);
 		else
 			owner = NULL;
-		preempt_disable();
-		raw_spin_unlock_irq(&lock->wait_lock);
-		wake_up_q(wake_q);
-		wake_q_init(wake_q);
-		preempt_enable();
+		raw_spin_unlock_irq_wake(&lock->wait_lock, wake_q);
 
 		if (!owner || !rtmutex_spin_on_owner(lock, &waiter, owner))
 			schedule_rtlock();
@@ -1893,10 +1874,7 @@ static __always_inline void __sched rtlock_slowlock(struct rt_mutex_base *lock)
 
 	raw_spin_lock_irqsave(&lock->wait_lock, flags);
 	rtlock_slowlock_locked(lock, &wake_q);
-	preempt_disable();
-	raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
-	wake_up_q(&wake_q);
-	preempt_enable();
+	raw_spin_unlock_irqrestore_wake(&lock->wait_lock, flags, &wake_q);
 }
 
 #endif /* RT_MUTEX_BUILD_SPINLOCKS */

kernel/locking/test-ww_mutex.c

@@ -404,7 +404,7 @@ static inline u32 prandom_u32_below(u32 ceil)
 static int *get_random_order(int count)
 {
 	int *order;
-	int n, r, tmp;
+	int n, r;
 
 	order = kmalloc_array(count, sizeof(*order), GFP_KERNEL);
 	if (!order)
@@ -415,11 +415,8 @@ static int *get_random_order(int count)
 
 	for (n = count - 1; n > 1; n--) {
 		r = prandom_u32_below(n + 1);
-		if (r != n) {
-			tmp = order[n];
-			order[n] = order[r];
-			order[r] = tmp;
-		}
+		if (r != n)
+			swap(order[n], order[r]);
 	}
 
 	return order;

kernel/smp.c

@@ -815,7 +815,8 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
 	WARN_ON_ONCE(!in_task());
 
 	/* Check if we need local execution. */
-	if ((scf_flags & SCF_RUN_LOCAL) && cpumask_test_cpu(this_cpu, mask))
+	if ((scf_flags & SCF_RUN_LOCAL) && cpumask_test_cpu(this_cpu, mask) &&
+	    (!cond_func || cond_func(this_cpu, info)))
 		run_local = true;
 
 	/* Check if we need remote execution, i.e., any CPU excluding this one. */
@@ -868,7 +869,7 @@ static void smp_call_function_many_cond(const struct cpumask *mask,
 			send_call_function_ipi_mask(cfd->cpumask_ipi);
 	}
 
-	if (run_local && (!cond_func || cond_func(this_cpu, info))) {
+	if (run_local) {
 		unsigned long flags;
 
 		local_irq_save(flags);

lib/Kconfig.debug

@@ -1397,9 +1397,9 @@ config PROVE_LOCKING
 	 For more details, see Documentation/locking/lockdep-design.rst.
 
 config PROVE_RAW_LOCK_NESTING
-	bool
+	bool "Enable raw_spinlock - spinlock nesting checks" if !ARCH_SUPPORTS_RT
 	depends on PROVE_LOCKING
-	default y
+	default y if ARCH_SUPPORTS_RT
 	help
 	 Enable the raw_spinlock vs. spinlock nesting checks which ensure
 	 that the lock nesting rules for PREEMPT_RT enabled kernels are
@@ -1502,41 +1502,41 @@ config LOCKDEP_SMALL
 	bool
 
 config LOCKDEP_BITS
-	int "Bitsize for MAX_LOCKDEP_ENTRIES"
+	int "Size for MAX_LOCKDEP_ENTRIES (as Nth power of 2)"
 	depends on LOCKDEP && !LOCKDEP_SMALL
-	range 10 30
+	range 10 24
 	default 15
 	help
 	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_ENTRIES too low!" message.
 
 config LOCKDEP_CHAINS_BITS
-	int "Bitsize for MAX_LOCKDEP_CHAINS"
+	int "Size for MAX_LOCKDEP_CHAINS (as Nth power of 2)"
 	depends on LOCKDEP && !LOCKDEP_SMALL
 	range 10 21
 	default 16
 	help
 	  Try increasing this value if you hit "BUG: MAX_LOCKDEP_CHAINS too low!" message.
 
 config LOCKDEP_STACK_TRACE_BITS
-	int "Bitsize for MAX_STACK_TRACE_ENTRIES"
+	int "Size for MAX_STACK_TRACE_ENTRIES (as Nth power of 2)"
 	depends on LOCKDEP && !LOCKDEP_SMALL
-	range 10 30
+	range 10 26
 	default 19
 	help
 	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
 
 config LOCKDEP_STACK_TRACE_HASH_BITS
-	int "Bitsize for STACK_TRACE_HASH_SIZE"
+	int "Size for STACK_TRACE_HASH_SIZE (as Nth power of 2)"
 	depends on LOCKDEP && !LOCKDEP_SMALL
-	range 10 30
+	range 10 26
 	default 14
 	help
 	  Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
 
 config LOCKDEP_CIRCULAR_QUEUE_BITS
-	int "Bitsize for elements in circular_queue struct"
+	int "Size for elements in circular_queue struct (as Nth power of 2)"
 	depends on LOCKDEP
-	range 10 30
+	range 10 26
 	default 12
 	help
 	  Try increasing this value if you hit "lockdep bfs error:-1" warning due to __cq_enqueue() failure.

rust/helpers/mutex.c

@@ -12,3 +12,8 @@ void rust_helper___mutex_init(struct mutex *mutex, const char *name,
 {
 	__mutex_init(mutex, name, key);
 }
+
+void rust_helper_mutex_assert_is_held(struct mutex *mutex)
+{
+	lockdep_assert_held(mutex);
+}

rust/helpers/spinlock.c

@@ -30,3 +30,8 @@ int rust_helper_spin_trylock(spinlock_t *lock)
 {
 	return spin_trylock(lock);
 }
+
+void rust_helper_spin_assert_is_held(spinlock_t *lock)
+{
+	lockdep_assert_held(lock);
+}

rust/kernel/sync.rs

@@ -16,8 +16,8 @@ pub mod poll;
 pub use arc::{Arc, ArcBorrow, UniqueArc};
 pub use condvar::{new_condvar, CondVar, CondVarTimeoutResult};
 pub use lock::global::{global_lock, GlobalGuard, GlobalLock, GlobalLockBackend, GlobalLockedBy};
-pub use lock::mutex::{new_mutex, Mutex};
-pub use lock::spinlock::{new_spinlock, SpinLock};
+pub use lock::mutex::{new_mutex, Mutex, MutexGuard};
+pub use lock::spinlock::{new_spinlock, SpinLock, SpinLockGuard};
 pub use locked_by::LockedBy;
 
 /// Represents a lockdep class. It's a wrapper around C's `lock_class_key`.