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Correct. One rseq TLS which contains a pointer to the current rseq_cs descriptor (or NULL), and possibly many rseq_cs critical section descriptors. > And you better not try to use it in a signal handler. The signal handler delivery handles the rseq abort on return to userspace. The rseq critical section can be used within a signal handler. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com