I added the following line to /etc/apparmor.d/usr.sbin.mysqld:
/sys/devices/system/cpu/ r,
then reloaded apparmor profile and that fixed the problem for me.
I added the following line to /etc/apparmor. d/usr.sbin. mysqld:
/sys/devices/ system/ cpu/ r,
then reloaded apparmor profile and that fixed the problem for me.