Comment 0 for bug 1843381

This is a bug reopen from
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1837700
The original one caused systemd regressed.
https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1842651

This issue needs an alternative solution.
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Dell has a feature called MAC addrss passthrough[1] that would force usb ethernet adapters to be assigned with a predefined MAC address stored in BIOS or so. This feature has been landed to mainline kernel in driver r8152[2]. So whenever a r8152 managed device is plugged into Dell devices with MAC addrss passthrough enabled, this driver will set NIC MAC to a predefined one.

And some Dell devices have already one built-in r8152 NIC port. On these devices, when a second r8152 NIC is plugged in, a Debian originated udev rules file 73-usb-net-by-mac.rules[3] will invoke udev built-in command `net_id` to give a persistent name, and that will be based on MAC address. However, since the system has already initialized the built-in r8152 NIC with that name, renaming the second interface with this name will always fail.

While Debian still carries a patch called "Revert-udev-network-device-renaming-immediately-give.patch"[4] that tries to keep support of already deprecated "75-persistent-net-generator.rules" based interface renaming mechanism, this patch also propagated into Ubuntu[5]. This patch will retry renaming with a 90 seconds timeout when the error code is -EEXIST, so the uevent processing will always be blocked in the last ifrename step in the victim system.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: udev 237-3ubuntu10.24 [modified: lib/udev/rules.d/50-firmware.rules lib/udev/rules.d/50-udev-default.rules lib/udev/rules.d/73-special-net-names.rules lib/udev/rules.d/73-usb-net-by-mac.rules]
ProcVersionSignature: Ubuntu 4.15.0-1043.48-oem 4.15.18
Uname: Linux 4.15.0-1043-oem x86_64
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
CustomUdevRuleFiles: 70-snap.core.rules 95-oem-hotkey-osd.rules
Date: Wed Jul 24 15:30:59 2019
DistributionChannelDescriptor:
 # This is the distribution channel descriptor for the OEM CDs
 # For more information see http://wiki.ubuntu.com/DistributionChannelDescriptor
 canonical-oem-somerville-bionic-amd64-20180608-47+beaver-jorah+X90
InstallationDate: Installed on 2019-07-03 (20 days ago)
InstallationMedia: Ubuntu 18.04 "Bionic" - Build amd64 LIVE Binary 20180608-09:38
MachineType: Dell Inc. Latitude 7424 Rugged Extreme
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-1043-oem.efi.signed root=UUID=5da90c85-3500-49a2-b989-71a604f9eec4 ro mem_sleep_default=deep quiet splash systemd.log_level=debug udev.log-priority=debug log_buf_len=8M vt.handoff=1
SourcePackage: systemd
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 05/27/2019
dmi.bios.vendor: Dell Inc.
dmi.bios.version: 1.5.0
dmi.board.name: 0Y7FK3
dmi.board.vendor: Dell Inc.
dmi.board.version: X03
dmi.chassis.type: 10
dmi.chassis.vendor: Dell Inc.
dmi.modalias: dmi:bvnDellInc.:bvr1.5.0:bd05/27/2019:svnDellInc.:pnLatitude7424RuggedExtreme:pvr:rvnDellInc.:rn0Y7FK3:rvrX03:cvnDellInc.:ct10:cvr:
dmi.product.family: Latitude
dmi.product.name: Latitude 7424 Rugged Extreme
dmi.sys.vendor: Dell Inc.

[1]: https://www.dell.com/support/article/tw/zh/twdhs1/sln301147/what-is-mac-address-pass-through?lang=en
[2]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/usb/r8152.c
[3]: https://salsa.debian.org/systemd-team/systemd/blob/master/debian/extra/rules/73-usb-net-by-mac.rules
[4]: https://salsa.debian.org/systemd-team/systemd/blob/master/debian/patches/debian/Revert-udev-network-device-renaming-immediately-give.patch
[5]: https://git.launchpad.net/~ubuntu-core-dev/ubuntu/+source/systemd/tree/debian/patches/debian/Revert-udev-network-device-renaming-immediately-give.patch?h=ubuntu-bionic