/usr/lib/sysctl.d/50-default.conf:kernel.sysrq = 16
https://www.kernel.org/doc/Documentation/sysrq.txt
0 - disable sysrq completely
1 - enable all functions of sysrq
>1 - bitmask of allowed sysrq functions (see below for detailed function
description):
2 = 0x2 - enable control of console logging level
4 = 0x4 - enable control of keyboard (SAK, unraw)
8 = 0x8 - enable debugging dumps of processes etc.
16 = 0x10 - enable sync command
32 = 0x20 - enable remount read-only
64 = 0x40 - enable signalling of processes (term, kill, oom-kill)
128 = 0x80 - allow reboot/poweroff
256 = 0x100 - allow nicing of all RT tasksめも、未検証
