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Description of problem: Microcode revision 0xdc for CPU 06-4e-03 (Skylake) can cause the system to freeze when applying the early microcode update. Late updates seem to be ok, at least on this system. [root@intel-skylake-y-01 ~]# lscpu | egrep -i -e family -e model -e stepping CPU family: 6 Model: 78 Model name: Intel(R) Core(TM) m5-6Y54 CPU @ 1.10GHz Stepping: 3 [root@intel-skylake-y-01 ~]# cat /sys/devices/system/cpu/cpu0/microcode/version 0x2d [root@intel-skylake-y-01 ~]# yum -y update microcode_ctl ... [root@intel-skylake-y-01 ~]# rpm -q microcode_ctl microcode_ctl-20191115-4.20200602.2.el8_2.x86_64 [root@intel-skylake-y-01 ~]# rpm -q --provides microcode_ctl | grep iucode_rev.*06-4e-03 iucode_rev(fname:intel/06-4e-03;cpuid:000406e3;pf_mask:0xc0) = 0xdc iucode_rev(fname:intel/06-4e-03;platform_id:0x40) = 0xdc iucode_rev(fname:intel/06-4e-03;platform_id:0x80) = 0xdc [root@intel-skylake-y-01 ~]# echo 1 > /sys/devices/system/cpu/microcode/reload [root@intel-skylake-y-01 ~]# cat /sys/devices/system/cpu/cpu0/microcode/version 0xdc [root@intel-skylake-y-01 ~]# dracut --force --early-microcode [root@intel-skylake-y-01 ~]# reboot ... <<<HANG AFTER GRUB SCREEN>>> Version-Release number of selected component (if applicable): microcode_ctl-20191115-4.20200602.2.el8_2.x86_64 How reproducible: always Steps to Reproduce: 1. install RHEL-8.2.0 2. apply z-stream update to microcode_ctl-20191115-4.20200602.2.el8_2.x86_64 3. dracut --force --early-ucode 4. reboot Actual results: hang after grub Expected results: normal boot Additional info: Upstream bug report: https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/31
06-5e-03 is to be blacklisted as well per [1]. [1] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/31#issuecomment-644885826
Verified with microcode_ctl-20200609-2.el8 By default, the microcode update is blacklisted on 06-4e-03 and 06-5e-03 systems and thus the tasks fail (since they're not running the latest microcode): https://beaker.engineering.redhat.com/recipes/8508203 https://beaker.engineering.redhat.com/recipes/8508205 If the microcode update is forced (with /etc/microcode_ctl/ucode_with_caveats/force-intel-06-4e-03 and force-intel-5e-03 files) then the 06-4e-03 system hangs (which is why it's blacklisted), and the 06-5e-03 system gets lucky and the update works and the tasks pass: https://beaker.engineering.redhat.com/recipes/8508204 https://beaker.engineering.redhat.com/recipes/8508206
(In reply to Jeff Bastian from comment #6) > If the microcode update is forced (with > /etc/microcode_ctl/ucode_with_caveats/force-intel-06-4e-03 and > force-intel-5e-03 files) then the 06-4e-03 system hangs Note: interrupting grub and adding dis_ucode_ldr to the kernel command line args allows the system to boot