[iotg][ehl] MAC address randomly changes on (re)boot

[Doug Jacobs]

[Summary]
Image: iotg-focal-desktop-20210813.img
CDTS running 20.04 Desktop Automated test suite.

During the reboot stress-test, the DUT will come up with a different MAC address, and therefore, a different IP address. This disrupts the automated tests, and sometimes causes CDTS to lose the test session entirely.

Example:
3: enp0s30f4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether ee:a6:98:c7:7c:c0 brd ff:ff:ff:ff:ff:ff
    inet 10.10.0.94/24 brd 10.10.0.255 scope global dynamic noprefixroute enp0s30f4
       valid_lft 2294sec preferred_lft 2294sec
    inet6 fe80::a29d:c74:9d67:1515/64 scope link noprefixroute
       valid_lft forever preferred_lft forever

(after a few reboots)

3: enp0s30f4: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq state UP group default qlen 1000
    link/ether 36:cd:a8:8a:3c:3a brd ff:ff:ff:ff:ff:ff
    inet 10.10.0.243/24 brd 10.10.0.255 scope global dynamic noprefixroute enp0s30f4
       valid_lft 2294sec preferred_lft 2294sec
    inet6 fe80::a29d:c74:9d67:1515/64 scope link noprefixroute
       valid_lft forever preferred_lft forever

[Steps to reproduce]
Connect DUT to an ethernet network with a DHCP server
Observe the DUT's IP address and MAC address with ip a
Reboot a few times

[Expected result]
MAC and IP addresses should always remain the same.

[Actual result]
Sometimes the MAC address will change, and the IP address along with it

[Failure rate] ~25-30%

[Additional information]
CID: 202105-29104
SKU:
system-manufacturer: Intel Corporation
system-product-name: Elkhart Lake Embedded Platform
bios-version: EHLSFWI1.R00.3162.A01.2104131432
CPU: Intel Atom(R) x6425RE Processor @ 1.90GHz (4x)
GPU: 00:02.0 VGA compatible controller [0300]: Intel Corporation Device [8086:4571] (rev 01)
kernel-version: 5.11.0-1012-intel

[Stage]
Issue reported and logs collected right after it happened

[Doug Jacobs (djacobs98)]

Automatically attached

[Doug Jacobs (djacobs98)]

Automatically attached

[Doug Jacobs (djacobs98)]

Automatically attached

[Doug Jacobs (djacobs98)]

Automatically attached

[Doug Jacobs (djacobs98)]

Note: This is different than issue: https://bugs.launchpad.net/intel/+bug/1941934

In that case, the MAC addresses and their IP addresses remained the same. However, both interfaces wouldn't always come up, so 1 would have its IP address and the other one wouldn't be configured.

[Alex Hung (alexhung)]

I recalled some systems require mac address to be written to EEPROM, and BIOS will copy the mac address during boot time. An example is demonstrated by a YouTube video https://www.youtube.com/watch?v=sIrgdNk35TU

This issue sounds like like BIOS is copying random data. So we may need to confirm with Intel that its BIOS behaviours and the mac address was written properly.

[Kent Lin (kent-jclin)]

This is fixed in Intel Corporation: EHLSFWI1.R00.3162.A01.2104131432 (UEFI)