Bug 691906 – sys-fs/udev-242 generates MAC address for bridge device instead of inheriting it from physical device

• Product: Gentoo Linux
• Status: RESOLVED UPSTREAM

[Description Jacek 2019-08-10 14:12:40 UTC]

sys-fs/udev-242 generate mac address for bridge instead of inherit it from phisical device

Reproducible: Always

Steps to Reproduce:
1. bridge created and has mac inherited from physical device
2. upgrade udev from 239 to 242
3. reboot - mac address is changed
Actual Results:  
mac address is changed

Expected Results:  
mac inherited from physical device

[Comment 1 Mike Gilbert 2019-08-12 19:39:43 UTC]

I don't think udev generates MAC addresses for bridge interfaces. Please provide more information about how you are creating this bridge interface.

[Comment 2 Mike Gilbert 2019-08-12 20:07:21 UTC]

Ok, this is happening because of MACAddressPolicy=persistent in /lib/systemd/network/99-default.link.

If you want the previous behavior, create a link file in /etc/systemd/network with the following content:

[Link]
NamePolicy=keep kernel database onboard slot path
MACAddressPolicy=none

I'm not sure why this changed between 239 and 242, but it seems like the current behavior is what upstream intended.

[Comment 3 Jacek 2019-08-13 09:13:24 UTC]

(In reply to Mike Gilbert from comment #1)
> I don't think udev generates MAC addresses for bridge interfaces. Please
> provide more information about how you are creating this bridge interface.

in /etc/conf.d/net
config_eno1="null"
config_eno2="null"

bridge_br0="eno1"
config_br0="dhcp"
brctl_br0="setfd 0 sethello 10 stp off"

Before udev242 bridge mac address was the same as eno1.
In udev242 mac is completely different.

Downgrade udev - restore mac address.

[Comment 4 Jacek 2019-08-13 09:29:59 UTC]

ok. after creating file with MACAddressPolicy=none
old behavior back.

But in udev239 there is also was MACAddressPolicy=persistent.