@ChatNoir
This is what I look at to determine the above
Mar 9 13:28:34 iron kernel: smpboot: CPU0: Intel(R) Core(TM) i7-10700 CPU @ 2.90GHz (family: 0x6, model: 0xa5, stepping: 0x5)
Mar 9 13:28:34 iron kernel: mce: [Hardware Error]: Machine check events logged
Mar 9 13:28:34 iron kernel: mce: [Hardware Error]: CPU 0: Machine Check: 0 Bank 6: ee0000000040110a
Mar 9 13:28:34 iron kernel: mce: [Hardware Error]: TSC 0 ADDR fef1e680 MISC 43880004086
Mar 9 13:28:34 iron kernel: mce: [Hardware Error]: PROCESSOR 0:a0655 TIME 1646861272 SOCKET 0 APIC 0 microcode ec
Mar 9 13:28:34 iron kernel: Performance Events: PEBS fmt3+, Skylake events, 32-deep LBR, full-width counters, Intel PMU driver.
Mar 9 13:28:34 iron kernel: ... version: 4
Mar 9 13:28:34 iron kernel: ... bit width: 48
Mar 9 13:28:34 iron kernel: ... generic registers: 4
Mar 9 13:28:34 iron kernel: ... value mask: 0000ffffffffffff
Mar 9 13:28:34 iron kernel: ... max period: 00007fffffffffff
Mar 9 13:28:34 iron kernel: ... fixed-purpose events: 3
Mar 9 13:28:34 iron kernel: ... event mask: 000000070000000f
Mar 9 13:28:34 iron kernel: rcu: Hierarchical SRCU implementation.
Mar 9 13:28:34 iron kernel: smp: Bringing up secondary CPUs ...
Mar 9 13:28:34 iron kernel: x86: Booting SMP configuration:
Mar 9 13:28:34 iron kernel: .... node #0, CPUs: #1 #2 #3 #4 #5 #6 #7 #8 #9 #10 #11 #12 #13 #14 #15
First line is the start of bringing the cores online and it ends at the last line. If there's an mce in the middle of it, its nothing to worry about.