similar issue, I had to restart udev for workaround after reboot
udiskd and udev processes consum many CPU, no dmesg nor errors in log.
# ps xfa|grep -c systemd-udevd
60
# top -n1|head -n 15
top - 22:01:12 up 2 min, 1 user, load average: 3.61, 1.75, 0.68
Tasks: 555 total, 3 running, 552...