[18:07] <ubot5> In #ubuntu-discuss, tomreyn said: !sysrq is <reply> In an emergency, you may be able to shutdown cleanly and reboot by holding down Alt+PrintScreen and typing slowly, in succession, S, U and B. For an explanation, see https://en.wikipedia.org/wiki/Magic_SysRq_key
[18:08] <dax> !sysrq
[18:08] <ubottu> In an emergency, you may be able to shutdown cleanly and reboot by holding down Alt+PrintScreen and typing slowly, in succession, R, E, I, S, U and B. For an explanation, see http://en.wikipedia.org/wiki/Magic_SysRq_key
[18:15] <ubot5> In #ubuntu-discuss, tomreyn said: !printk is <reply> If your !tty is flooded with error messages, you can limit the kernel logging daemons' log level below the default of 4 (KERN_WARNING), e.g. by running "echo 3 | sudo tee -a /proc/sys/kernel/printk". More info at https://wiki.ubuntu.com/Kernel/KernelDebuggingTricks#printk_is_your_friend and syslog(2)
[18:18] <tomreyn> dax: diff is mostly that sysrq suggested pressing all of REISUB when only SUB works (due to the limiter that was introduced years ago to prevent physical attacks) and that printk was previously wrong, suggested raising the printk when it should be lowered.
[18:18] <tomreyn> (my mistake there)
[18:20] <dax> !printk
[18:20] <ubottu> If your !tty is full of error messages, you can raise the kernel logging daemons' log level above the default of 4 (KERN_WARNING), e.g. by running "echo 7 | sudo tee -a /proc/sys/kernel/printk". More info at https://wiki.ubuntu.com/Kernel/KernelDebuggingTricks#printk_is_your_friend
[18:20] <dax> !-printk
[18:20] <ubottu> printk has no aliases - added by Unit193 on 2019-09-23 00:41:31
[18:21] <dax> ubottu: no, printk is <reply> If your !tty is flooded with error messages, you can limit the kernel logging daemons' log level below the default of 4 (KERN_WARNING), e.g. by running "echo 3 | sudo tee -a /proc/sys/kernel/printk". More info at https://wiki.ubuntu.com/Kernel/KernelDebuggingTricks#printk_is_your_friend and syslog(2)
[18:21] <ubottu> I'll remember that dax
[18:22] <dax> tomreyn: are R,E,I disabled on all supported ubuntu versions?
[18:23] <tomreyn> dax: i would think definitely on generic kernels since 16.04, do not know about -oem (probably, too, based on how its patchset was described to me), do not know about ubuntu core.
[18:24] <dax> !-sysrq
[18:24] <ubottu> sysrq aliases: reisub - added by ompaul on 2008-09-12 20:29:51 - last edited by rww on 2016-02-16 19:59:18
[18:24] <dax> ubottu: sysrq =~ s/R, E, I, //
[18:24] <ubottu> I'll remember that dax
[18:24] <dax> !sysrq
[18:24] <ubottu> In an emergency, you may be able to shutdown cleanly and reboot by holding down Alt+PrintScreen and typing slowly, in succession, S, U and B. For an explanation, see http://en.wikipedia.org/wiki/Magic_SysRq_key
[18:26] <tomreyn> thank you!
[18:35] <tomreyn> dax: https://www.kernel.org/doc/Documentation/admin-guide/sysrq.rst would be the 'official' (but not necessarily newbie friendly) sysrq manual and /etc/sysctl.d/10-magic-sysrq.conf defines the restrictions of which keys are supported on ubuntu systems.
[18:39] <tomreyn> in addition to user space, the sysrq restrictions are also baked into kernels via CONFIGs: grep -i SYSRQ /boot/config-$(uname -r)
[18:39] <dax> yup. i'm at work and don't have an ubuntu handy, so wasn't sure which ones were enabled
[18:41] <tomreyn> the kernel restrictions are way more loose,though
[18:41] <tomreyn> i won't bug you more ;)