Re:RDRAND on AMD Ryzen 9 5900X is flakey
by jeroenhd on Monday January 11, 2021 @07:25PM
(#25740471)
Why does systemd need super random, unique numbers? Why can't it fall back on something like a PRNG until /dev/(u)random gains enough entropy?
The original crash report generates an error for a file name already existing. A simple PRNG algorithm, perhaps seeded with a "random" RDRAND number, should fit that purpose easily, shouldn't it?
A 32 bit random number, as used to generate the examples, isn't good enough to guarantee uniqueness anyway. It seems like the original reporter's specific CPU silicon or their loaded microcode does have a problem (because the boot fails on that particular chip so often) but the general dependency on RDRAND continues to confuse me.
The original crash report generates an error for a file name already existing. A simple PRNG algorithm, perhaps seeded with a "random" RDRAND number, should fit that purpose easily, shouldn't it?
A 32 bit random number, as used to generate the examples, isn't good enough to guarantee uniqueness anyway. It seems like the original reporter's specific CPU silicon or their loaded microcode does have a problem (because the boot fails on that particular chip so often) but the general dependency on RDRAND continues to confuse me.