Merge tag 'locking-core-2026-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull locking updates from Ingo Molnar:
 "Lock debugging:

   - Implement compiler-driven static analysis locking context checking,
     using the upcoming Clang 22 compiler's context analysis features
     (Marco Elver)

     We removed Sparse context analysis support, because prior to
     removal even a defconfig kernel produced 1,700+ context tracking
     Sparse warnings, the overwhelming majority of which are false
     positives. On an allmodconfig kernel the number of false positive
     context tracking Sparse warnings grows to over 5,200... On the plus
     side of the balance actual locking bugs found by Sparse context
     analysis is also rather ... sparse: I found only 3 such commits in
     the last 3 years. So the rate of false positives and the
     maintenance overhead is rather high and there appears to be no
     active policy in place to achieve a zero-warnings baseline to move
     the annotations & fixers to developers who introduce new code.

     Clang context analysis is more complete and more aggressive in
     trying to find bugs, at least in principle. Plus it has a different
     model to enabling it: it's enabled subsystem by subsystem, which
     results in zero warnings on all relevant kernel builds (as far as
     our testing managed to cover it). Which allowed us to enable it by
     default, similar to other compiler warnings, with the expectation
     that there are no warnings going forward. This enforces a
     zero-warnings baseline on clang-22+ builds (Which are still limited
     in distribution, admittedly)

     Hopefully the Clang approach can lead to a more maintainable
     zero-warnings status quo and policy, with more and more subsystems
     and drivers enabling the feature. Context tracking can be enabled
     for all kernel code via WARN_CONTEXT_ANALYSIS_ALL=y (default
     disabled), but this will generate a lot of false positives.

     ( Having said that, Sparse support could still be added back,
       if anyone is interested - the removal patch is still
       relatively straightforward to revert at this stage. )

  Rust integration updates: (Alice Ryhl, Fujita Tomonori, Boqun Feng)

    - Add support for Atomic<i8/i16/bool> and replace most Rust native
      AtomicBool usages with Atomic<bool>

    - Clean up LockClassKey and improve its documentation

    - Add missing Send and Sync trait implementation for SetOnce

    - Make ARef Unpin as it is supposed to be

    - Add __rust_helper to a few Rust helpers as a preparation for
      helper LTO

    - Inline various lock related functions to avoid additional function
      calls

  WW mutexes:

    - Extend ww_mutex tests and other test-ww_mutex updates (John
      Stultz)

  Misc fixes and cleanups:

    - rcu: Mark lockdep_assert_rcu_helper() __always_inline (Arnd
      Bergmann)

    - locking/local_lock: Include more missing headers (Peter Zijlstra)

    - seqlock: fix scoped_seqlock_read kernel-doc (Randy Dunlap)

    - rust: sync: Replace `kernel::c_str!` with C-Strings (Tamir
      Duberstein)"

* tag 'locking-core-2026-02-08' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (90 commits)
  locking/rwlock: Fix write_trylock_irqsave() with CONFIG_INLINE_WRITE_TRYLOCK
  rcu: Mark lockdep_assert_rcu_helper() __always_inline
  compiler-context-analysis: Remove __assume_ctx_lock from initializers
  tomoyo: Use scoped init guard
  crypto: Use scoped init guard
  kcov: Use scoped init guard
  compiler-context-analysis: Introduce scoped init guards
  cleanup: Make __DEFINE_LOCK_GUARD handle commas in initializers
  seqlock: fix scoped_seqlock_read kernel-doc
  tools: Update context analysis macros in compiler_types.h
  rust: sync: Replace `kernel::c_str!` with C-Strings
  rust: sync: Inline various lock related methods
  rust: helpers: Move #define __rust_helper out of atomic.c
  rust: wait: Add __rust_helper to helpers
  rust: time: Add __rust_helper to helpers
  rust: task: Add __rust_helper to helpers
  rust: sync: Add __rust_helper to helpers
  rust: refcount: Add __rust_helper to helpers
  rust: rcu: Add __rust_helper to helpers
  rust: processor: Add __rust_helper to helpers
  ...

6 files changed, 36 insertions, 27 deletions

diff --git a/mm/kfence/Makefile b/mm/kfence/Makefile
index 2de2a58d11a1..a503e83e74d9 100644
--- a/mm/kfence/Makefile
+++ b/mm/kfence/Makefile
@@ -1,5 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0
 
+CONTEXT_ANALYSIS := y
+
 obj-y := core.o report.o
 
 CFLAGS_kfence_test.o := -fno-omit-frame-pointer -fno-optimize-sibling-calls
diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index 4f79ec720752..653e162fa494 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -133,8 +133,8 @@ struct kfence_metadata *kfence_metadata __read_mostly;
 static struct kfence_metadata *kfence_metadata_init __read_mostly;
 
 /* Freelist with available objects. */
-static struct list_head kfence_freelist = LIST_HEAD_INIT(kfence_freelist);
-static DEFINE_RAW_SPINLOCK(kfence_freelist_lock); /* Lock protecting freelist. */
+DEFINE_RAW_SPINLOCK(kfence_freelist_lock); /* Lock protecting freelist. */
+static struct list_head kfence_freelist __guarded_by(&kfence_freelist_lock) = LIST_HEAD_INIT(kfence_freelist);
 
 /*
  * The static key to set up a KFENCE allocation; or if static keys are not used
@@ -254,6 +254,7 @@ static bool kfence_unprotect(unsigned long addr)
 }
 
 static inline unsigned long metadata_to_pageaddr(const struct kfence_metadata *meta)
+	__must_hold(&meta->lock)
 {
 	unsigned long offset = (meta - kfence_metadata + 1) * PAGE_SIZE * 2;
 	unsigned long pageaddr = (unsigned long)&__kfence_pool[offset];
@@ -289,6 +290,7 @@ static inline bool kfence_obj_allocated(const struct kfence_metadata *meta)
 static noinline void
 metadata_update_state(struct kfence_metadata *meta, enum kfence_object_state next,
 		      unsigned long *stack_entries, size_t num_stack_entries)
+	__must_hold(&meta->lock)
 {
 	struct kfence_track *track =
 		next == KFENCE_OBJECT_ALLOCATED ? &meta->alloc_track : &meta->free_track;
@@ -486,7 +488,7 @@ static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t g
 	alloc_covered_add(alloc_stack_hash, 1);
 
 	/* Set required slab fields. */
-	slab = virt_to_slab((void *)meta->addr);
+	slab = virt_to_slab(addr);
 	slab->slab_cache = cache;
 	slab->objects = 1;
 
@@ -515,6 +517,7 @@ static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t g
 static void kfence_guarded_free(void *addr, struct kfence_metadata *meta, bool zombie)
 {
 	struct kcsan_scoped_access assert_page_exclusive;
+	u32 alloc_stack_hash;
 	unsigned long flags;
 	bool init;
 
@@ -547,9 +550,10 @@ static void kfence_guarded_free(void *addr, struct kfence_metadata *meta, bool z
 	/* Mark the object as freed. */
 	metadata_update_state(meta, KFENCE_OBJECT_FREED, NULL, 0);
 	init = slab_want_init_on_free(meta->cache);
+	alloc_stack_hash = meta->alloc_stack_hash;
 	raw_spin_unlock_irqrestore(&meta->lock, flags);
 
-	alloc_covered_add(meta->alloc_stack_hash, -1);
+	alloc_covered_add(alloc_stack_hash, -1);
 
 	/* Check canary bytes for memory corruption. */
 	check_canary(meta);
@@ -594,6 +598,7 @@ static void rcu_guarded_free(struct rcu_head *h)
  * which partial initialization succeeded.
  */
 static unsigned long kfence_init_pool(void)
+	__context_unsafe(/* constructor */)
 {
 	unsigned long addr, start_pfn;
 	int i, rand;
@@ -1242,6 +1247,7 @@ bool kfence_handle_page_fault(unsigned long addr, bool is_write, struct pt_regs
 {
 	const int page_index = (addr - (unsigned long)__kfence_pool) / PAGE_SIZE;
 	struct kfence_metadata *to_report = NULL;
+	unsigned long unprotected_page = 0;
 	enum kfence_error_type error_type;
 	unsigned long flags;
 
@@ -1275,9 +1281,8 @@ bool kfence_handle_page_fault(unsigned long addr, bool is_write, struct pt_regs
 		if (!to_report)
 			goto out;
 
-		raw_spin_lock_irqsave(&to_report->lock, flags);
-		to_report->unprotected_page = addr;
 		error_type = KFENCE_ERROR_OOB;
+		unprotected_page = addr;
 
 		/*
 		 * If the object was freed before we took the look we can still
@@ -1289,7 +1294,6 @@ bool kfence_handle_page_fault(unsigned long addr, bool is_write, struct pt_regs
 		if (!to_report)
 			goto out;
 
-		raw_spin_lock_irqsave(&to_report->lock, flags);
 		error_type = KFENCE_ERROR_UAF;
 		/*
 		 * We may race with __kfence_alloc(), and it is possible that a
@@ -1301,6 +1305,8 @@ bool kfence_handle_page_fault(unsigned long addr, bool is_write, struct pt_regs
 
 out:
 	if (to_report) {
+		raw_spin_lock_irqsave(&to_report->lock, flags);
+		to_report->unprotected_page = unprotected_page;
 		kfence_report_error(addr, is_write, regs, to_report, error_type);
 		raw_spin_unlock_irqrestore(&to_report->lock, flags);
 	} else {
diff --git a/mm/kfence/kfence.h b/mm/kfence/kfence.h
index dfba5ea06b01..f9caea007246 100644
--- a/mm/kfence/kfence.h
+++ b/mm/kfence/kfence.h
@@ -34,6 +34,8 @@
 /* Maximum stack depth for reports. */
 #define KFENCE_STACK_DEPTH 64
 
+extern raw_spinlock_t kfence_freelist_lock;
+
 /* KFENCE object states. */
 enum kfence_object_state {
 	KFENCE_OBJECT_UNUSED,		/* Object is unused. */
@@ -53,7 +55,7 @@ struct kfence_track {
 
 /* KFENCE metadata per guarded allocation. */
 struct kfence_metadata {
-	struct list_head list;		/* Freelist node; access under kfence_freelist_lock. */
+	struct list_head list __guarded_by(&kfence_freelist_lock);	/* Freelist node. */
 	struct rcu_head rcu_head;	/* For delayed freeing. */
 
 	/*
@@ -91,13 +93,13 @@ struct kfence_metadata {
 	 * In case of an invalid access, the page that was unprotected; we
 	 * optimistically only store one address.
 	 */
-	unsigned long unprotected_page;
+	unsigned long unprotected_page __guarded_by(&lock);
 
 	/* Allocation and free stack information. */
-	struct kfence_track alloc_track;
-	struct kfence_track free_track;
+	struct kfence_track alloc_track __guarded_by(&lock);
+	struct kfence_track free_track __guarded_by(&lock);
 	/* For updating alloc_covered on frees. */
-	u32 alloc_stack_hash;
+	u32 alloc_stack_hash __guarded_by(&lock);
 #ifdef CONFIG_MEMCG
 	struct slabobj_ext obj_exts;
 #endif
@@ -141,6 +143,6 @@ enum kfence_error_type {
 void kfence_report_error(unsigned long address, bool is_write, struct pt_regs *regs,
 			 const struct kfence_metadata *meta, enum kfence_error_type type);
 
-void kfence_print_object(struct seq_file *seq, const struct kfence_metadata *meta);
+void kfence_print_object(struct seq_file *seq, const struct kfence_metadata *meta) __must_hold(&meta->lock);
 
 #endif /* MM_KFENCE_KFENCE_H */
diff --git a/mm/kfence/report.c b/mm/kfence/report.c
index 10e6802a2edf..787e87c26926 100644
--- a/mm/kfence/report.c
+++ b/mm/kfence/report.c
@@ -106,6 +106,7 @@ found:
 
 static void kfence_print_stack(struct seq_file *seq, const struct kfence_metadata *meta,
 			       bool show_alloc)
+	__must_hold(&meta->lock)
 {
 	const struct kfence_track *track = show_alloc ? &meta->alloc_track : &meta->free_track;
 	u64 ts_sec = track->ts_nsec;
@@ -207,8 +208,6 @@ void kfence_report_error(unsigned long address, bool is_write, struct pt_regs *r
 	if (WARN_ON(type != KFENCE_ERROR_INVALID && !meta))
 		return;
 
-	if (meta)
-		lockdep_assert_held(&meta->lock);
 	/*
 	 * Because we may generate reports in printk-unfriendly parts of the
 	 * kernel, such as scheduler code, the use of printk() could deadlock.
@@ -263,6 +262,7 @@ void kfence_report_error(unsigned long address, bool is_write, struct pt_regs *r
 	stack_trace_print(stack_entries + skipnr, num_stack_entries - skipnr, 0);
 
 	if (meta) {
+		lockdep_assert_held(&meta->lock);
 		pr_err("\n");
 		kfence_print_object(NULL, meta);
 	}
diff --git a/mm/memory.c b/mm/memory.c
index da360a6eb8a4..b2909c94e249 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2213,8 +2213,8 @@ static pmd_t *walk_to_pmd(struct mm_struct *mm, unsigned long addr)
 	return pmd;
 }
 
-pte_t *__get_locked_pte(struct mm_struct *mm, unsigned long addr,
-			spinlock_t **ptl)
+pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr,
+		      spinlock_t **ptl)
 {
 	pmd_t *pmd = walk_to_pmd(mm, addr);
 
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index d3aec7a9926a..af7966169d69 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -280,7 +280,7 @@ static unsigned long pmdp_get_lockless_start(void) { return 0; }
 static void pmdp_get_lockless_end(unsigned long irqflags) { }
 #endif
 
-pte_t *___pte_offset_map(pmd_t *pmd, unsigned long addr, pmd_t *pmdvalp)
+pte_t *__pte_offset_map(pmd_t *pmd, unsigned long addr, pmd_t *pmdvalp)
 {
 	unsigned long irqflags;
 	pmd_t pmdval;
@@ -332,13 +332,12 @@ pte_t *pte_offset_map_rw_nolock(struct mm_struct *mm, pmd_t *pmd,
 }
 
 /*
- * pte_offset_map_lock(mm, pmd, addr, ptlp), and its internal implementation
- * __pte_offset_map_lock() below, is usually called with the pmd pointer for
- * addr, reached by walking down the mm's pgd, p4d, pud for addr: either while
- * holding mmap_lock or vma lock for read or for write; or in truncate or rmap
- * context, while holding file's i_mmap_lock or anon_vma lock for read (or for
- * write). In a few cases, it may be used with pmd pointing to a pmd_t already
- * copied to or constructed on the stack.
+ * pte_offset_map_lock(mm, pmd, addr, ptlp) is usually called with the pmd
+ * pointer for addr, reached by walking down the mm's pgd, p4d, pud for addr:
+ * either while holding mmap_lock or vma lock for read or for write; or in
+ * truncate or rmap context, while holding file's i_mmap_lock or anon_vma lock
+ * for read (or for write). In a few cases, it may be used with pmd pointing to
+ * a pmd_t already copied to or constructed on the stack.
  *
  * When successful, it returns the pte pointer for addr, with its page table
  * kmapped if necessary (when CONFIG_HIGHPTE), and locked against concurrent
@@ -389,8 +388,8 @@ pte_t *pte_offset_map_rw_nolock(struct mm_struct *mm, pmd_t *pmd,
  * table, and may not use RCU at all: "outsiders" like khugepaged should avoid
  * pte_offset_map() and co once the vma is detached from mm or mm_users is zero.
  */
-pte_t *__pte_offset_map_lock(struct mm_struct *mm, pmd_t *pmd,
-			     unsigned long addr, spinlock_t **ptlp)
+pte_t *pte_offset_map_lock(struct mm_struct *mm, pmd_t *pmd,
+			   unsigned long addr, spinlock_t **ptlp)
 {
 	spinlock_t *ptl;
 	pmd_t pmdval;