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Documentation: Add documentation for Compiler-Based Context Analysis Adds documentation in Documentation/dev-tools/context-analysis.rst, and adds it to the index. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20251219154418.3592607-5-elver@google.com 2025-12-19 16:39:53 +01:00


















compiler-context-analysis: Bump required Clang version to 23 Clang 23 introduces several major improvements: 1. Support for multiple arguments in the `guarded_by` and `pt_guarded_by` attributes [1]. This allows defining variables protected by multiple context locks, where read access requires holding at least one lock (shared or exclusive), and write access requires holding all of them exclusively. 2. Function pointer support [2]. We can now add attributes to function pointers just like we do on normal functions. 3. A fix to use arrays of locks [3]. Each index is now correctly treated as a separate lock instance. 4. A fix for implicit member access in attributes [4]. This allows to use __guarded_by(&foo->lock) correctly. Overall that makes it worthwhile bumping the compiler version instead of trying to make both Clang 22 and later work while supporting these new features. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Link: https://github.com/llvm/llvm-project/pull/186838 [1] Link: https://github.com/llvm/llvm-project/pull/191187 [2] Link: https://github.com/llvm/llvm-project/pull/148551 [3] Link: https://github.com/llvm/llvm-project/pull/194457 [4] Link: https://patch.msgid.link/20260515124426.2227783-1-elver@google.com 2026-05-15 14:43:31 +02:00
Documentation: Add documentation for Compiler-Based Context Analysis Adds documentation in Documentation/dev-tools/context-analysis.rst, and adds it to the index. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20251219154418.3592607-5-elver@google.com 2025-12-19 16:39:53 +01:00



























































locking/rwlock, spinlock: Support Clang's context analysis Add support for Clang's context analysis for raw_spinlock_t, spinlock_t, and rwlock. This wholesale conversion is required because all three of them are interdependent. To avoid warnings in constructors, the initialization functions mark a lock as acquired when initialized before guarded variables. The test verifies that common patterns do not generate false positives. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20251219154418.3592607-9-elver@google.com 2025-12-19 16:39:57 +01:00
bit_spinlock: Support Clang's context analysis The annotations for bit_spinlock.h have simply been using "bitlock" as the token. For Sparse, that was likely sufficient in most cases. But Clang's context analysis is more precise, and we need to ensure we can distinguish different bitlocks. To do so, add a token context, and a macro __bitlock(bitnum, addr) that is used to construct unique per-bitlock tokens. Add the appropriate test. <linux/list_bl.h> is implicitly included through other includes, and requires 2 annotations to indicate that acquisition (without release) and release (without prior acquisition) of its bitlock is intended. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20251219154418.3592607-14-elver@google.com 2025-12-19 16:40:02 +01:00
locking/ww_mutex: Support Clang's context analysis Add support for Clang's context analysis for ww_mutex. The programming model for ww_mutex is subtly more complex than other locking primitives when using ww_acquire_ctx. Encoding the respective pre-conditions for ww_mutex lock/unlock based on ww_acquire_ctx state using Clang's context analysis makes incorrect use of the API harder. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20251219154418.3592607-21-elver@google.com 2025-12-19 16:40:09 +01:00

Documentation: Add documentation for Compiler-Based Context Analysis Adds documentation in Documentation/dev-tools/context-analysis.rst, and adds it to the index. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20251219154418.3592607-5-elver@google.com 2025-12-19 16:39:53 +01:00
compiler-context-analysis: Introduce scoped init guards Add scoped init guard definitions for common synchronization primitives supported by context analysis. The scoped init guards treat the context as active within initialization scope of the underlying context lock, given initialization implies exclusive access to the underlying object. This allows initialization of guarded members without disabling context analysis, while documenting initialization from subsequent usage. The documentation is updated with the new recommendation. Where scoped init guards are not provided or cannot be implemented (ww_mutex omitted for lack of multi-arg guard initializers), the alternative is to just disable context analysis where guarded members are initialized. Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/all/20251212095943.GM3911114@noisy.programming.kicks-ass.net/ Link: https://patch.msgid.link/20260119094029.1344361-3-elver@google.com 2026-01-19 10:05:52 +01:00


























Documentation: Add documentation for Compiler-Based Context Analysis Adds documentation in Documentation/dev-tools/context-analysis.rst, and adds it to the index. Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20251219154418.3592607-5-elver@google.com 2025-12-19 16:39:53 +01:00

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169 lines

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