SoylentNews

An Anonymous Coward writes:

As long time SoylentNews community member Marand observed during some recent discussion of severe systemd boot problems, it turns out that systemd disables the magic SysRq key.

The magic SysReq key is described at Wikipedia as:

[...] a key combination understood by the Linux kernel, which allows the user to perform various low-level commands regardless of the system's state. It is often used to recover from freezes, or to reboot a computer without corrupting the filesystem.

A Fedora user who logged a bug report for this issue back in 2013 described the problem with systemd's unexpected and harmful default setting:

As systemd depends on many files on a rootfs, in case of any problems with rootfs, it is not able to do its basic function - control processes and (cleanly) shutdown/reboot when crtl-alt-del is pressed on local keyboard. As this is a feature, I'd like to ask to enable the sysrq by default on Fedora, otherwise it is not possible to reboot system even locally in case of emergency situation.

While that Fedora bug report is set to CLOSED NOTABUG, other Linux distros, like Mageia and Debian GNU/Linux, have restored the proper behavior.

Now that this problem has come to light, all Fedora users should evaluate whether or not they need to fix their systems to work around systemd's incorrect default setting. Users of other Linux distributions using systemd should also evaluate their systems, too, in case their distro has not yet fixed this unexpected bug.