shims: fix a subtle bug in semaphore initialisation on Windows #791
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This function is the initializer for the semaphore. The seamphore storage itself may be stack allocated (or heap allocated) but without guarantee of 0-initialisation. As a result, the subsequent CAS for the atomic replacement will fail silently, leaving the previously non-zero value in place, indicating that the value is a valid handle. This would fail randomly and would ultimately result in a crash in the `CloseHandle` call associated with the clean up. This issue was identified by SwiftLint on Windows.
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@swift-ci please test |
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This function is the initializer for the semaphore. The seamphore storage itself may be stack allocated (or heap allocated) but without guarantee of 0-initialisation. As a result, the subsequent CAS for the atomic replacement will fail silently, leaving the previously non-zero value in place, indicating that the value is a valid handle. This would fail randomly and would ultimately result in a crash in the
CloseHandlecall associated with the clean up.This issue was identified by SwiftLint on Windows.