Notifier error injection

modulename: notifier-error-inject.ko

configname: CONFIG_NOTIFIER_ERROR_INJECTION

Linux Kernel Configuration
└─>Kernel hacking
└─>Notifier error injection
In linux kernel since version 3.1 (release Date: 2011-10-24)  
This option provides the ability to inject artificial errors to
specified notifier chain callbacks. It is useful to test the error
handling of notifier call chain failures.

Say N if unsure.

source code:
lib/notifier-error-inject.c
selects
CONFIG_DEBUG_FS