OP, what Linux is this? I'm really curious, I don't recognize that trace format and I can't find the code to print exception traces with the eight bangs on the first line like that anywhere in the upstream git history. I think they're actually from the BIOS?
!!!! X64 Exception Type - 12(#MC - Machine-Check) CPU Apic ID - 00000000 !!!!
My story: I had an Intel NUC running Linux back in the day, which would get stuck in standby such that I had to remove and replace the CMOS battery to get it to boot again! I never figured that one out...
This is a trace from the BIOS, it is not uncommon to have them printed over the serial console. Potentially the BIOS is based on EDK2 source code, in which case you can take a look here for the implementation of the trace printing logic: https://github.com/tianocore/edk2/blob/9e6537469d4700d9d793e...
