The original design for the 64-bit futex had the token count replicated in the high part. But the constructor wasn't setting it. This is one of the issues I had noticed when investigating QTBUG-66875, but didn't need to address since the the fix I ended up applying in commit 081c001deb75fa38385d3ff8cbbdb4f788529133 made that unnecessary: the high part only had the number of waiters. Unfortunately, when commit f502270c0f06daba75c1da381bd1658d81aa7bba brought back the token count in the high part, I failed to correct that problem. As a consequence, every QSemaphore that was initialized in the constructor to a non-zero value would eventually deadlock. This commit fixes that oversight. Task-number: QTBUG-67481 Change-Id: I662b8f168c74440ab1a8fffd1522be6b85adb4d0 Reviewed-by: Lars Knoll <lars.knoll@qt.io> Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io> Reviewed-by: Svenn-Arne Dragly <svenn-arne.dragly@qt.io>