CONFIG_HAVE_ARCH_KFENCE (not configurable)

configname: CONFIG_HAVE_ARCH_KFENCE

Linux Kernel Configuration
└─>Kernel hacking
└─>Memory Debugging
└─>HAVE_ARCH_KFENCE
In linux kernel since version 5.2 (release Date: 2019-07-07)  
is selected by
CONFIG_KFENCE