KernelCare update. Error unpatching [255] ('default', '', '', False)

Issue

KernelCare update is failed:

# kcarectl --update
Updates already downloaded
Error unpatching [255] ('default', '', '', False)

# /usr/bin/kcarectl --patch-info
Update available, run 'kcarectl --update'. 

Environment

• KernelCare

Solution

There are two ways to solve the problem:

1) reboot the server

2) analyze the dmesg, find the processes causing the problem and stop them, then run kcarectl --update manually - and do this procedure only once!

For example:

[45678910.479053] kpatch: safety check failed for 'unix_stream_read_generic.kpatch' ffffffff89311c70/ffffffffc0a8af70 (task 10388:virtlogd)
[45678910.479053] kpatch: safety check failed for 'kvm_vcpu_ioctl.kpatch' ffffffffc076dcb0/ffffffffc0b80780 (task 10406:CPU 0/KVM)
[45678910.479053] kpatch: safety check failed for 'kvm_vcpu_ioctl.kpatch' ffffffffc076dcb0/ffffffffc0b80780 (task 10407:CPU 1/KVM)
[45678910.479053] kpatch: safety check failed for 'kvm_vcpu_ioctl.kpatch' ffffffffc076dcb0/ffffffffc0b80780 (task 10408:CPU 2/KVM)

virtlogd (task 10388:virtlogd) and KVM VM’s (task 10406:CPU 0/KVM) need to be stopped.

Cause

This message means that the KernelCare update failed, however, the old patch is still in place.