Hello, Can you please help with an interesting problem. I have an Intel Haswell based processor with CentOS 7.0 with an early kernel booting and running perfectly. I changed the processor to an Ice Lake and I get the problem below when I boot the working Haswell disk. The boot process hangs almost immediately and when I remove the 'quiet' boot parameter I see that it hangs randomly, usually with a high CPU number, when SMPBOOT is starting up the cores. The only solution I have found is to boot with the 'nr_cpus=8 (could be any low number), update to the latest kernel then reboot with the 'nr_cpus=8' parameter removed. On examination there are no problems with CentOS 7.4 and above but there are with CentOS 7.3 and below.
I think the issue is quite clear here: the newer CPU is not handled correctly by the old kernel - maybe it even doesn't know this CPU type and doesn't know how to detect the number of cores it has.
I don't think there is a better solution than what you already did.
Regards, Simon