Merge tag 'locking-core-2026-04-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Ingo Molnar:
 "Mutexes:

   - Add killable flavor to guard definitions (Davidlohr Bueso)

   - Remove the list_head from struct mutex (Matthew Wilcox)

   - Rename mutex_init_lockep() (Davidlohr Bueso)

  rwsems:

   - Remove the list_head from struct rw_semaphore and
     replace it with a single pointer (Matthew Wilcox)

   - Fix logic error in rwsem_del_waiter() (Andrei Vagin)

  Semaphores:

   - Remove the list_head from struct semaphore (Matthew Wilcox)

  Jump labels:

   - Use ATOMIC_INIT() for initialization of .enabled (Thomas Weißschuh)

   - Remove workaround for old compilers in initializations
     (Thomas Weißschuh)

  Lock context analysis changes and improvements:

   - Add context analysis for rwsems (Peter Zijlstra)

   - Fix rwlock and spinlock lock context annotations (Bart Van Assche)

   - Fix rwlock support in <linux/spinlock_up.h> (Bart Van Assche)

   - Add lock context annotations in the spinlock implementation
     (Bart Van Assche)

   - signal: Fix the lock_task_sighand() annotation (Bart Van Assche)

   - ww-mutex: Fix the ww_acquire_ctx function annotations
     (Bart Van Assche)

   - Add lock context support in do_raw_{read,write}_trylock()
     (Bart Van Assche)

   - arm64, compiler-context-analysis: Permit alias analysis through
     __READ_ONCE() with CONFIG_LTO=y (Marco Elver)

   - Add __cond_releases() (Peter Zijlstra)

   - Add context analysis for mutexes (Peter Zijlstra)

   - Add context analysis for rtmutexes (Peter Zijlstra)

   - Convert futexes to compiler context analysis (Peter Zijlstra)

  Rust integration updates:

   - Add atomic fetch_sub() implementation (Andreas Hindborg)

   - Refactor various rust_helper_ methods for expansion (Boqun Feng)

   - Add Atomic<*{mut,const} T> support (Boqun Feng)

   - Add atomic operation helpers over raw pointers (Boqun Feng)

   - Add performance-optimal Flag type for atomic booleans, to avoid
     slow byte-sized RMWs on architectures that don't support them.
     (FUJITA Tomonori)

   - Misc cleanups and fixes (Andreas Hindborg, Boqun Feng, FUJITA
     Tomonori)

  LTO support updates:

   - arm64: Optimize __READ_ONCE() with CONFIG_LTO=y (Marco Elver)

   - compiler: Simplify generic RELOC_HIDE() (Marco Elver)

  Miscellaneous fixes and cleanups by Peter Zijlstra, Randy Dunlap,
  Thomas Weißschuh, Davidlohr Bueso and Mikhail Gavrilov"

* tag 'locking-core-2026-04-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (39 commits)
  compiler: Simplify generic RELOC_HIDE()
  locking: Add lock context annotations in the spinlock implementation
  locking: Add lock context support in do_raw_{read,write}_trylock()
  locking: Fix rwlock support in <linux/spinlock_up.h>
  lockdep: Raise default stack trace limits when KASAN is enabled
  cleanup: Optimize guards
  jump_label: remove workaround for old compilers in initializations
  jump_label: use ATOMIC_INIT() for initialization of .enabled
  futex: Convert to compiler context analysis
  locking/rwsem: Fix logic error in rwsem_del_waiter()
  locking/rwsem: Add context analysis
  locking/rtmutex: Add context analysis
  locking/mutex: Add context analysis
  compiler-context-analysys: Add __cond_releases()
  locking/mutex: Remove the list_head from struct mutex
  locking/semaphore: Remove the list_head from struct semaphore
  locking/rwsem: Remove the list_head from struct rw_semaphore
  rust: atomic: Update a safety comment in impl of `fetch_add()`
  rust: sync: atomic: Update documentation for `fetch_add()`
  rust: sync: atomic: Add fetch_sub()
  ...

2 files changed, 19 insertions, 0 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 94eb2667b7e1..aac60b6cfa4b 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1618,14 +1618,22 @@ config LOCKDEP_STACK_TRACE_BITS
 	int "Size for MAX_STACK_TRACE_ENTRIES (as Nth power of 2)"
 	depends on LOCKDEP && !LOCKDEP_SMALL
 	range 10 26
+	default 21 if KASAN
 	default 19
 	help
 	  Try increasing this value if you hit "BUG: MAX_STACK_TRACE_ENTRIES too low!" message.
 
+	  KASAN significantly increases stack trace consumption because its
+	  slab tracking interacts with lockdep's dependency validation under
+	  PREEMPT_FULL, creating a feedback loop.  The higher default when
+	  KASAN is enabled costs ~12MB extra, which is negligible compared to
+	  KASAN's own shadow memory overhead.
+
 config LOCKDEP_STACK_TRACE_HASH_BITS
 	int "Size for STACK_TRACE_HASH_SIZE (as Nth power of 2)"
 	depends on LOCKDEP && !LOCKDEP_SMALL
 	range 10 26
+	default 16 if KASAN
 	default 14
 	help
 	  Try increasing this value if you need large STACK_TRACE_HASH_SIZE.
diff --git a/lib/test_context-analysis.c b/lib/test_context-analysis.c
index 140efa8a9763..06b4a6a028e0 100644
--- a/lib/test_context-analysis.c
+++ b/lib/test_context-analysis.c
@@ -596,3 +596,14 @@ static void __used test_ww_mutex_lock_ctx(struct test_ww_mutex_data *d)
 
 	ww_mutex_destroy(&d->mtx);
 }
+
+static DEFINE_PER_CPU(raw_spinlock_t, test_per_cpu_lock);
+
+static void __used test_per_cpu(int cpu)
+{
+	raw_spin_lock(&per_cpu(test_per_cpu_lock, cpu));
+	raw_spin_unlock(&per_cpu(test_per_cpu_lock, cpu));
+
+	raw_spin_lock(per_cpu_ptr(&test_per_cpu_lock, cpu));
+	raw_spin_unlock(per_cpu_ptr(&test_per_cpu_lock, cpu));
+}