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My aim is to use this vDSO as a replacement for atomic xchg and atomic cmpxchg within library code. I am trying to make the transition as straightforward as possible considering that this is a design bug fix. If adding error handling at that precise point of the libc robust mutex unlock code is straightforward, I don't mind internally checking flags and returning -EINVAL, but I'd want to hear about preference from the libc people on this topic beforehand. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com