Udev high CPU usage

Since a few days udev has a high CPU usage.

When I run udevadm monitor I get this infinitely.

UDEV  [523.831696] add      /devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.0/0003:1770:FF00.4F98 (hid)
UDEV  [523.833418] bind     /devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.0 (usb)
UDEV  [523.834606] remove   /devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.0/0003:1770:FF00.4F98 (hid)
UDEV  [523.835886] unbind   /devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.0 (usb)
KERNEL[523.850026] remove   /devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.0/0003:1770:FF00.4F9A (hid)
KERNEL[523.850070] unbind   /devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.0 (usb)
KERNEL[523.853485] add      /devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.0/0003:1770:FF00.4F9B (hid)
KERNEL[523.853540] bind     /devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.0 (usb)
UDEV  [523.853966] add      /devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.0/0003:1770:FF00.4F99 (hid)
UDEV  [523.855605] bind     /devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.0 (usb)
UDEV  [523.856728] remove   /devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.0/0003:1770:FF00.4F99 (hid)
UDEV  [523.857876] unbind   /devices/pci0000:00/0000:00:14.0/usb1/1-7/1-7:1.0 (usb)

if run

sudo systemctl restart systemd-udevd systemd-udevd-kernel.socket systemd-udevd-control.socket

it works fine for few hours.

I don’t change my hardware (some laptop, same devices…). I think is a software update.

My kernel is 5.9.11-3-MANJARO

All my system is updated to manjaro stable.

I have been experiencing the exact same issue. I tried turning off the wifi and bluetooth as well as removing any external device but it didn’t change anything.

Don’t know if it helps but running /lib/systemd/systemd-udevd -D output the following codes :

1-7:1.0: SEQNUM=141434 blocked by SEQNUM=141257
0003:1770:FF00.8664: SEQNUM=141435 blocked by SEQNUM=141258
1-7:1.0: SEQNUM=141436 blocked by SEQNUM=141257
0003:1770:FF00.8637: Device (SEQNUM=141257, ACTION=remove) processed
0003:1770:FF00.8637: sd-device-monitor: Passed 348 byte to netlink monitor
1-7:1.0: Device (SEQNUM=141258, ACTION=unbind) ready for processing
1-7:1.0: sd-device-monitor: Passed 238 byte to netlink monitor
1-7:1.0: SEQNUM=141260 blocked by SEQNUM=141258

My kernel is 5.8.18-1

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I format my computer and install Manjaro again. For few days, all works fine but now, I have high cpu usage from udev.

@Warks did you get anything?

The issue is still the same for me. I’ve got used to restarting the services at boot. I try to look for someone reporting the same issue every now and then but nothing comes up. If I ever find anything I will post it here.

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Alright so I finally figured it out !

I have a MSI gaming laptop with a backlit keyboard. The backlit isn’t supported by default so I had to install this MSIKLM tool to make it work. When autostart is enabled, it creates a udev rules that is, for some reasons, incompatible with my setup. Removing the rules fixed the issue. I will create a post directly to the github to further investigate the problem.

Now in case your setup is different, here is what I did to figure out which device was creating the issue:

First I ran udevadm monitor to get the device name (which you already did).

Then I went to the corresponding folder at /sys/bus/usb/devices/1-7/1-7:1.0/. In there, there was a folder named 0003:1770:FF00.0EC2 which should rougly correspond to the name you get from udevadm monitor

I had a look around and found a file called uevent which gave me the name of the device, i.e my keyboard. From there, I just remembered than I had installed a package to manage the backlight of my keyboard and tried removing it.

I hope that this will help you !


The problem was the Steel Series Keyboard, the file /etc/udev/rules.d/90-msiklm.rules from msiklm provoque the infinity loop.