ThreadSanitizer triage: recover the missing synchronization contract
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Read both conflicting access paths and repair the ownership or synchronization rule that connects them.
What it is
ThreadSanitizer detects data races using compiler instrumentation and a runtime library. Clang documents -fsanitize=thread for compilation and linking, with debug information for actionable source locations. The report connects conflicting accesses and thread creation context; it is evidence about an executed concurrent interaction, not a complete specification of the intended algorithm. Clang ThreadSanitizer
Why it matters
A coding agent can silence a report by surrounding the named line with a lock while leaving other accesses outside the same discipline. Instead, identify who owns the state, when ownership transfers, and what synchronization establishes access order. A coherent rule should explain every path touching the object.
How to apply
- Read both access stacks and locate the shared object. Separate its construction, ordinary updates, publication and destruction; lifetime errors can cross the same thread boundary as updates.
- State the intended contract: exclusively owned by one thread, protected by one named mutex, or communicated through a specified synchronization mechanism. Compare all accesses with that contract.
- Make the smallest change that restores the contract. If replacing shared mutation with message passing, document who owns the object before and after delivery.
- Propose a fixture that deliberately coordinates the competing operations, avoiding arbitrary sleeps as the only mechanism for exercising overlap. Include shutdown or cancellation if the reported interaction occurs there.
- Rerun the relevant instrumented workload and the ordinary suite. Record excluded or uninstrumented components and any suppression that limits the conclusion.
Pitfalls
A race-free implementation can still have logical ordering bugs or deadlocks. A clean run also does not prove every scheduling interleaving was exercised. Instrumentation and ignorelists affect what the tool observes; the documentation warns that omitted instrumentation can obscure synchronization and stack information. Treat a suppression as a scoped limitation to explain, not as evidence that the underlying ownership rule is correct.
範囲と根拠
Original synthesis from the cited primary documentation, with proposed diagnostic and verification steps. No benchmark, experiment or field result is claimed; unreviewed AI-assisted contribution.
知識の基準日：2026-09-22。状態：unreviewed（レビュー記録なし） — 編集するとレビュー状態はリセットされます。本文は未検証の参考情報として扱い、出典を確認してください。
出典
- Clang ThreadSanitizer — 2026-09-23 確認：到達可能、引用箇所あり
帰属とライセンス
- Account External coding curation authors (57eb56c9)
- Written with Codex, an AI coding agent, at the site operator's request; original synthesis, sources credited separately.
最新の変更： New English original; AI-assisted and unreviewed. Proposed checks have not been executed for this article.
オリジナルの投稿： CC BY 4.0. リンク先の出典はそれぞれの権利を保持します。