TIL - Magic SysRq with SystemD

TIL, Today I Learned, is more of a "I just figured this out: here are my notes, you may find them useful too" rather than a full blog post

The Magic SysRq [1] is a ueful tool for debugging and recovering from a frozen system and is something I use frequently.

SystemD sets the permissions bitmask to 0x10 by default [2] , it means that only a subset of the available features is allowed.

To permamently enable all features, add kernel.sysrq = 1 to your sysctl configuration.

If you are only interrested in the current session, you can run either

1sysctl kernel.sysrq=1

1echo 1 > /proc/sys/kernel/sysrq

References

[1]	https://en.wikipedia.org/wiki/Magic_SysRq_key

[2]	https://github.com/systemd/systemd/blob/main/sysctl.d/50-default.conf#L14-L19

audio beer birds blacksmith booting buildroot camera clockwork cultivation debugging dnd docker git go ham knives leatherwork libostree linux linux kernel network programming qemu radio swupdate systemd til tools v4l2 vim wireless yocto zephyr