Log user space messages

configname: CONFIG_PSTORE_PMSG

Linux Kernel Configuration
└─>File systems
└─>Miscellaneous filesystems
└─>Log user space messages
In linux kernel since version 4 (release Date: 2015-04-12)  
When the option is enabled, pstore will export a character
interface /dev/pmsg0 to log user space messages. On reboot
data can be retrieved from /sys/fs/pstore/pmsg-ramoops-[ID].

If unsure, say N.

selects
CONFIG_RT_MUTEXES