I've been having this problem for a while now, after each update when eopkg tried to apply the udev rules I got this error message:
[✓] Reloading udev rules success [✗] Applying udev rules failed A copy of the command output follows: Failed to write 'change' to '/sys/devices/virtual/input/input56/uevent': Cannot allocate memory Failed to write 'change' to '/sys/devices/virtual/input/input57/uevent': Cannot allocate memory
I figured it must have been a kernel bug or something so I didn't bother looking into it. But it been multiple months now so I looked at what those two virtual devices are:
tzig@solus-arrr ~ $ cat /sys/devices/virtual/input/input56/name ckb1: Corsair Gaming SABRE RGB Laser Mouse vKB tzig@solus-arrr ~ $ cat /sys/devices/virtual/input/input57/name ckb1: Corsair Gaming SABRE RGB Laser Mouse vM
I unplugged my mouse and started sudo usysconf run -f, it applied rules without any issue
I then tried to sudo systemctl stop ckb-next-daemon, plugged in my mouse and ran sudo usysconf run -f again, usysconf applied udev rules fine.
Looked on ckb-next github for an issue resembling mine, I can't find any so it might be Solus specific