On 17/08/2021 16:34, Simon Matter wrote: >> 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 > Exactly what I was thinking. CentOS 7.0 released in 2014, Intel Ice Lake released at least 5 years later so there will be no support for Ice Lake in the CentOS 7.0 kernel. I'm surprised there is any support in 7.4. Why are you not using the latest release?