RDRAND on AMD Ryzen 9 5900X is flakey

Re:RDRAND on AMD Ryzen 9 5900X is flakey by chmod775 on Monday January 11, 2021 @06:14PM (#25739369)

So you actually want them to wrap RDRAND in their own random number generator?

> UUID generation should be robust to random number collisions.

The UUID standards say that nowhere at all, it is only acknowledged that collisions may happen even if they are unlikely.

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Re:RDRAND on AMD Ryzen 9 5900X is flakey by citrin_ru on Monday January 11, 2021 @07:54PM (#25740771)

Purpose of UUID is to be unique, not random. There is no need to wrap RDRAND into another random generator. One can use time/counter as one part of UUID and kernel provided PRNG, e. g. getrandom(2) for another part.

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Re:RDRAND on AMD Ryzen 9 5900X is flakey by segfaultbuserr on Monday January 11, 2021 @08:15PM (#25740972)

> getrandom(2) for another part.

But you cannot use getrandom().

During early boot, the kernel will either block indefinitely and/or log the uninitialized urandom read as a security problem. It was the entire reason that brought systemd's rdrand code into existence.

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