Hello.

Judging by the initial description, the issue could be similar to

https://bugzilla.redhat.com/show_bug.cgi?id=1630681
https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/1

It is presumed that it is linked to bugs in firmware/BIOS.

May I ask for CPU model/microcode information? "grep -E '^(cpu family|model|stepping|microcode)' /proc/cpuinfo | sort -u" or "lscpu" output, at least, would suffice.

Thank you.

Eugene,
Here is the command output you requested. Thanks.

[operator@localhost ~]$ grep -E '^(cpu family|model|stepping|microcode)' /proc/cpuinfo | sort -u
cpu family	: 6
microcode	: 0xca
model		: 158
model name	: Intel(R) Xeon(R) E-2186M  CPU @ 2.90GHz
stepping	: 10

[operator@localhost ~]$ lscpu
Architecture:        x86_64
CPU op-mode(s):      32-bit, 64-bit
Byte Order:          Little Endian
CPU(s):              12
On-line CPU(s) list: 0-11
Thread(s) per core:  2
Core(s) per socket:  6
Socket(s):           1
NUMA node(s):        1
Vendor ID:           GenuineIntel
CPU family:          6
Model:               158
Model name:          Intel(R) Xeon(R) E-2186M  CPU @ 2.90GHz
Stepping:            10
CPU MHz:             800.079
CPU max MHz:         4800.0000
CPU min MHz:         800.0000
BogoMIPS:            5808.00
Virtualization:      VT-x
L1d cache:           32K
L1i cache:           32K
L2 cache:            256K
L3 cache:            12288K
NUMA node0 CPU(s):   0-11
Flags:               fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf tsc_known_freq pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault epb invpcid_single pti ssbd ibrs ibpb stibp tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm mpx rdseed adx smap clflushopt intel_pt xsaveopt xsavec xgetbv1 xsaves dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp md_clear flush_l1d

Thank you.  It might be similar to [1][2] (considering the similarity between 06-8e-0X/06-9e-0X designs and the fact that the systems have the same vendor).  There are reports[3] that the newer 0xd6 microcode revision, part of microcode-2020609 release[4][5][6][7], solves the hangs for some, but not always[8].

[1] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/24
[2] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/24
[3] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/23#issuecomment-641903218
[4] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/releases/tag/microcode-20200609
[5] https://access.redhat.com/solutions/5142751
[6] https://access.redhat.com/errata/RHSA-2020:2431 
[7] https://access.redhat.com/downloads/content/rhel---8/x86_64/7416/microcode_ctl/20191115-4.20200602.2.el8_2/x86_64/fd431d51/package
[8] https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/24#issuecomment-643099897

Eugene,
Thanks very much for sharing your expertise on this issue. RHSA-2020:2431 seems to indicate Red Hat is working to address the microcode_ctl compatibility issues with this family of Intel processors. Hopefully, this fix will be included in updated RHEL 8.x installation media soon. Thanks again.

Verified with microcode_ctl-20200609-2.el8

By default, the microcode update is blocked to avoid CPU freezes.  Creating the appropriate force file under /etc/microcode_ctl/ucode_with_caveats allows the microcode update to proceed (for systems which have been tested and confirmed that it's safe to update the microcode).

[root@dell-pet140-01 ~]# rpm -q microcode_ctl
microcode_ctl-20200609-2.el8.x86_64

[root@dell-pet140-01 ~]# lscpu | grep -i -e family -e model -e stepping
CPU family:          6
Model:               158
Model name:          Intel(R) Celeron(R) G4900 CPU @ 3.10GHz
Stepping:            11

[root@dell-pet140-01 ~]# journalctl --boot 0 --no-hostname --output short-monotonic --no-pager --grep=microcode
-- Logs begin at Wed 2020-07-01 13:48:29 EDT, end at Wed 2020-07-01 17:49:27 EDT. --
[    0.000000] kernel: microcode: microcode updated early to revision 0xb4, date = 2019-04-01
[    0.058002] kernel: SRBDS: Vulnerable: No microcode
[    1.985951] kernel: microcode: sig=0x906eb, pf=0x2, revision=0xb4
[    1.991478] kernel: microcode: Microcode Update Driver: v2.2.
[   14.226036] systemd[1]: Starting Load CPU microcode update...
[   14.997187] systemd[1]: microcode.service: Succeeded.
[   14.997457] systemd[1]: Started Load CPU microcode update.

[root@dell-pet140-01 ~]# touch /etc/microcode_ctl/ucode_with_caveats/force-intel-06-8e-9e-0x-dell

[root@dell-pet140-01 ~]# /usr/libexec/microcode_ctl/update_ucode 

[root@dell-pet140-01 ~]# dracut --force

[root@dell-pet140-01 ~]# reboot
...

[root@dell-pet140-01 ~]# journalctl --boot 0 --no-hostname --output short-monotonic --no-pager --grep=microcode
-- Logs begin at Wed 2020-07-01 14:03:24 EDT, end at Wed 2020-07-01 18:04:43 EDT. --
[    0.000000] kernel: microcode: microcode updated early to revision 0xd6, date = 2020-04-23
[    0.058005] kernel: SRBDS: Mitigation: Microcode
[    2.030070] kernel: microcode: sig=0x906eb, pf=0x2, revision=0xd6
[    2.035600] kernel: microcode: Microcode Update Driver: v2.2.
[   14.335791] systemd[1]: Starting Load CPU microcode update...
[   15.292972] systemd[1]: microcode.service: Succeeded.
[   15.293318] systemd[1]: Started Load CPU microcode update.

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (microcode_ctl bug fix and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHEA-2020:4489