How to fix triggering repetitive udevadm "change" event which causes 100% CPU core use?

Question

This is a top process from the top command

643 root      20   0   93856  74480   3940 R 100.0   0.3 131:25.50 systemd-udevd  

This is the output from udevadm monitor

KERNEL[16222.287655] change   /devices/pci0000:00/0000:00:14.0/usb2/2-3/2-3:1.0/host0/target0:0:0/0:0:0:0/block/sda (block)

The event above keeps being triggered.

I already tried removing USB devices(apart from Logitech mouse) and apply this solution. It did not help.

When I restart udevd services it goes back go normal for a while but then starts again. How do I fix this?

May block/sda mean that it's related to /dev/sda1 which is my MicroSD in the card reader?

Answer 1

Yes, the device being detected by udev is a block device, aka a storage device. If your MicroSD is sda (sda1 is the partition, sda is the device) then it does refer to your MicroSD card.

The "change" event in question is triggered when the storage media inside a storage device gets removed/inserted or switched (ex card reader stays the same, but the card inside gets removed/switched with a new one).

It sounds like your device is mistakenly detecting the SD card being repeatedly being removed and reinserted. You can try removing and reinserting the MicroSD to see if perhaps it's a faulty hardware connection or something like that.