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Bug in /dev/serial/by-id

Source

Original message by @shiftingtech on the VORONDesign Discord server.
It has been edited here for the purpose of editoral clarification.

A bug has been introduced in the udev software package (part of the systemd package) present in Debian Bullseye (which includes Armbian and current MainsailOS) which prevents the symbolic links to serial devices in /dev/serial/by-id/ from being created.

As of May 20th 2023, this bug has spread to PiOS based systems as well.

This bug may cause the following issues:

  1. Your printer can’t connect to the motherboard’s microcontroller (MCU) anymore after a system update

    Klipper MCU can't connect

  2. ls /dev/serial/by-id shows no devices or warns you the file does not exist

     $ ls /dev/serial/by-id
 ls: cannot access '/dev/serial/by-id': No such file or directory

Am I affected?

Before asserting whether you are affected by this bug, assess whether your motherboard is being recognized and shows up as a device.

  1. Connect your motherboard to the Pi using a suitable USB cable.

  2. Run lsusb and observe the output for any devices containing “OpenMoko, Inc.”

     $ lsusb
 Bus 001 Device 001 1234:ABCD OpenMoko, Inc.

❎ If your motherboard does not show up as such, it may be the case that:

  • Your motherboard isn’t connected to the Pi
    Have you tried plugging it in?
  • The Klipper firmware on your motherboard was flashed improperly
    Follow the correct instructions for flashing your board with firmware.
  • The Klipper firmware on your motherboard failed to flash
    Check the SD-card for evidence of the flashing process succeeding.
  • The Klipper firmware on your motherboard was not built for the right device
    Make sure you have selected the right options for your motherboard under make menuconfig
  • The USB cable connecting your motherboard to the Pi is defective
    Try a different USB cable.
  • Your motherboard is having other issues

✅ If your motherboard does show up as such, then proceed as follows:

Check whether you are affected by this bug by checking the version of the installed udev package by running apt show udev in the terminal.

The following versions are known to be affected:

  • 247.3-7+deb11u2
  • 247.3-7+rpi1+deb11u2

Please note the last section of the version string, including u2.

Solution A

Replacing the corrupted file from the udev package with that from a version that is not affected.

  1. Back up the existing file (in case you need it)
    sudo cp /usr/lib/udev/rules.d/60-serial.rules /usr/lib/udev/rules.d/60-serial.old
  2. Download the patched file from the systemd repository
    sudo wget -O /usr/lib/udev/rules.d/60-serial.rules https://raw.githubusercontent.com/systemd/systemd/main/rules.d/60-serial.rules
  3. Reboot the machine/Pi
    sudo reboot

Solution B

Installing a patched version of the software package from the Debian “Backports” software repositories.

Raspberry Pi OS (& Raspbian)

Do not attempt Solution B on machines/Pi’s running PiOS-based systems (previously named Rasbian)!
If you are unsure of what your operating system type is, stick to Solution A.

To install the patched version of the systemd package (version 252.5-2~bpo11+1):

  1. Copy and paste the following command as one line.
    Use the “Copy” icon top-right of the code block to help you with this.

     cd ~;wget http://ftp.us.debian.org/debian/pool/main/s/systemd/libudev1_252.5-2~bpo11+1_`dpkg --print-architecture`.deb http://ftp.us.debian.org/debian/pool/main/s/systemd/udev_252.5-2~bpo11+1_`dpkg --print-architecture`.deb;APT_LISTCHANGES_FRONTEND=none sudo apt install --fix-broken ./libudev1_252.5-2~bpo11+1_`dpkg --print-architecture`.deb ./udev_252.5-2~bpo11+1_`dpkg --print-architecture`.deb; rm libudev1_252.5-2~bpo11+1_`dpkg --print-architecture`.deb udev_252.5-2~bpo11+1_`dpkg --print-architecture`.deb

    If all goes right, this command should be prompting or attempting to install only the two affected packages (udev and libudev).

    If the command tries to install other packages or behaves unexpectedly (in particular, wanting to remove a large quantity of installed packages), stop the command using CTRL+C and reassess the situation.

  2. Reboot
    sudo reboot

You should now be able to see your device in /dev/serial/by-id and/or connect to your device in Klipper once again.