Add futex wake-path store-buffering reproduction - #1228
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Weiteng Chen (CvvT) wants to merge 1 commit into
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Add futex wake-path store-buffering reproduction#1228Weiteng Chen (CvvT) wants to merge 1 commit into
Weiteng Chen (CvvT) wants to merge 1 commit into
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Reproduce the lost wakeup where FutexManager::wake's relaxed `done` store races the waiter's SeqCst `WAITING` store: on x86 TSO each side can read the other's stale value, so the waker's fetch_update observes RUNNING_IN_HOST and skips the wake while the waiter blocks and times out. Add a test-only `ordering_stress` rendezvous module, compiled under cfg(test) or the new `futex_ordering_stress` feature, that aligns the two conflicting stores and records whether each side saw the other's old value. - litebox: ignored probabilistic `stress_registered_waiter_does_not_miss_wake` over the mock platform, driving the real wake/fetch_update path. - litebox_platform_linux_userland: a real-platform liveness stress test plus a feature-gated tight reproduction exercising real FUTEX_WAIT/FUTEX_WAKE.
Weiteng Chen (CvvT)
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🤖 SemverChecks 🤖 No breaking API changes detected Note: this does not mean API is unchanged, or even that there are no breaking changes; simply, none of the detections triggered. |
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Reproduce the lost wakeup where FutexManager::wake's relaxed
donestore races the waiter's SeqCstWAITINGstore: on x86 TSO each side can read the other's stale value, so the waker's fetch_update observes RUNNING_IN_HOST and skips the wake while the waiter blocks and times out.Add a test-only
ordering_stressrendezvous module, compiled under cfg(test) or the newfutex_ordering_stressfeature, that aligns the two conflicting stores and records whether each side saw the other's old value.Two unit tests added to trigger the bug: one using mock platform and the other one uses Linux platform. To run them:
See #820 for more details about this bug.