Bug 1846119 - [rhel-8.3.0] skylake (06-4e-03) microcode update hangs
Summary: [rhel-8.3.0] skylake (06-4e-03) microcode update hangs
Keywords:
Status: VERIFIED
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: microcode_ctl
Version: 8.2
Hardware: x86_64
OS: Linux
medium
medium
Target Milestone: rc
: 8.3
Assignee: Eugene Syromiatnikov
QA Contact: Jeff Bastian
URL:
Whiteboard:
Depends On:
Blocks: 1848438 1848439 1848440
TreeView+ depends on / blocked
 
Reported: 2020-06-10 20:00 UTC by Jeff Bastian
Modified: 2020-07-01 20:51 UTC (History)
1 user (show)

Fixed In Version: microcode_ctl-20200609-1.el8
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Doc Text:
Clone Of:
: 1846133 1846134 1848438 1848439 1848440 (view as bug list)
Environment:
Last Closed:
Type: Bug
Target Upstream Version:


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Description Jeff Bastian 2020-06-10 20:00:03 UTC
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

Comment 1 Eugene Syromiatnikov 2020-06-16 17:44:19 UTC
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

Comment 6 Jeff Bastian 2020-07-01 20:47:06 UTC
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

Comment 7 Jeff Bastian 2020-07-01 20:51:33 UTC
(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


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