On the rare lock occasions

kernelhead · 07-09-2022, 08:53 PM

For years, I've used Ctrl+Print Screen+R+E+I+S+U+B (holding down Ctrl and Print Screen while managing to press those 6 keys in order...

Just curious what others do, or perhaps what is safe(r)...

frankbell · 07-09-2022, 08:58 PM

I usually turn off lock screen, but, on the rare occasions I forget, I just log back in.

Or am I missing something in your question?

kernelhead · 07-09-2022, 09:28 PM

Quote:

Originally Posted by frankbell

I usually turn off lock screen, but, on the rare occasions I forget, I just log back in.

Or am I missing something in your question?

Yea I think you're missing something (smiles). I'm referring to a computer lock up...

I know one can Google this, but I'm curious as to what users here do...

frankbell · 07-09-2022, 09:33 PM

Okay, thanks. I thought you were referring to a "lock screen."

If my GUI locks up, I usually use CTRL-F[#] to switch to a different workspace, login as root, and reboot.

If that doesn't work (and it always has so far), I power off and restart.

hazel · 07-10-2022, 06:37 AM

I've tried the REISUB thing a few times but have never got it to work!

My solution, if I can't get a virtual console, is to turn off at the mains, then reboot. In the old days, that would lead to scolding about disks not being cleanly unmounted and you had to run fsck, but modern journalling filesystems don't seem to mind about that.

syg00 · 07-10-2022, 07:02 AM

Hmmm.

Most people don't even try I suspect. But you gotta get it to work - check the (kernel) config to ensure sysrq is enabled. Stomping on incomplete filesystem updates will come unstuck one day, mark my words.
The kernel devs (usually) try to give you the means to not shoot yourself in the foot - but it's your finger on the trigger.

!!! · 07-10-2022, 09:38 AM

Don't forget the famous (old?) Control Alt backspace

https://bbs.archlinux.org/viewtopic.php?id=73617

Also be sure (if you have another device on the network) to try the obvious thing of SSH and ping from another machine

hazel · 07-10-2022, 09:42 AM

Quote:

Originally Posted by !!!

Don't forget the famous (old?) Control Alt backspace

Always worth trying. But it won't work when your keyboard's locked up!

DavidMcCann · 07-10-2022, 10:22 AM

Quote:

Originally Posted by hazel

I've tried the REISUB thing a few times but have never got it to work!

Some distros disable the SysRq key for some reason. Check /etc/sysctl.conf and make sure it has kernel.sysrq = 1. For more information, see https://wiki.archlinux.org/title/Keyboard_shortcuts

hazel · 07-10-2022, 10:31 AM

Slackware doesn't have a built-in sysctl.conf but I checked /proc/sys/kernel/sysrq and it is set to 1.

fatmac · 07-10-2022, 01:22 PM

If my computer freezes up, it's time to switch off power, the journal will normally return it to a usable state quickly enough, but if it has corrupted the file system, fsck may come to the rescue, failing that, I'll just re install - I keep good backups of my data.

SlowCoder · 07-10-2022, 02:19 PM

I must be doing something right, because I haven't had a lockup in about a year. I resorted to the magic SysRq sequence once, and it did as expected. No dirty filesystem errors on reboot. But that's on my desktop. Never done it on a server.

It's important wait a period of time between each key, to give the kernel time to complete operations, especially filesystem syncing.

hazel · 07-11-2022, 03:54 AM

Quote:

Originally Posted by SlowCoder

I must be doing something right, because I haven't had a lockup in about a year.

I had a couple of lockups when experimenting with vivaldi. There's a thread here maintained by its admirers so I thought I'd give it a try. When I saw that it locked up my machine, I dropped it like a hot brick. That was a couple of years ago and I haven't had any trouble since then.

Quote:

It's important wait a period of time between each key, to give the kernel time to complete operations, especially filesystem syncing.

Maybe that's why it wouldn't work for me. How long is one supposed to wait?

yancek · 07-11-2022, 06:01 AM

I began using the REISUB method about a year ago and it has never failed for me. I've never had a problem with just typing the keys at a normal rate although I will say needs to be certain to press the key hard enough.

pan64 · 07-11-2022, 06:12 AM

https://en.wikipedia.org/wiki/Magic_SysRq_key

Quote:

Before the advent of journaled filesystems a common use of the magic SysRq key was to perform a safe reboot of a Linux computer which has otherwise locked up (abbr. REISUB), which avoided a risk of filesystem corruption. With modern filesystems, this practice is discouraged, offering no upsides over straight reBoot.