Why sysrq is limited to only "sync" command on official fedora kernel?

[Josh Boyer]

On Wed, Feb 25, 2015 at 9:35 AM, Ali AlipourR <alipoor90 at gmail.com> wrote:
>>> Why sysrq is limited to only "sync" command on official fedora kernel?
>>
>> The kernel itself isn't limited.  It's just set that way in
>> /usr/lib/sysctl.d/50-default.conf which is provided by systemd.  You
>> can edit that file, create your own in /etc/sysctrl.d/, or (as root)
>> set it to whatever you would like via /proc/sys/kernel/sysrq.
>
> Of course it can be changed at runtime, but I mean why official fedora
> kernel shouldn't be configured to allow all (or at least a wider
> subset) of sysrq commands by default?

Maybe we're getting hung up on a terminology issue, but this isn't a
kernel configuration issue.  It's something userspace is doing.

> This way official fedora live CDs are unsuitable for system recovery
> tasks; you have to change sysrq value every time you use live CDs or
> build your own live CD.

That's a good point.  Since the live images have a "rescue" mode,
maybe there is a way to use a different value when booted into that.
How that would look, I'm not sure.  Maybe dracut would need to include
an override file in the initramfs.

josh