HOW-TO reboot only if all else fails

[xyz]

I searched the forum but didn't find this HowTo. Sorry if I missed it somehow.

I learned it when I was using Mandriva.
If your system doesn't react at all, you are totally stuck, and even Ctrl+Alt+backspace gives nothing, try and 'save' the following phrase somewhere in your mind:

Raising Skinny Elephants Is Utterly Boring

Hit the following key sequences; do give it some time between each keystrokes:
( SysRq = print screen ) (Use the LEFT Alt key )
Alt+SysRq+r
Alt+SysRq+s
Alt+SysRq+e
Alt+SysRq+i
Alt+SysRq+u
Alt+SysRq+b

The r stands for put keyboard in raw mode
The s for sync the disk
The e for terminate all processes
The i for kill all processes
The u for remount all filesystems read only
The b for reboot the system

Use it as a procedure only if all else fails!!

Please pay attention to the following:
PS: If your filesystem is Ext3 or ReiserFS and on reboot it wants you to do a filesystem check, don't touch any key when it asks you to press "Y" and let it recover the journal automatically.

NOTE: For the skinny elephants to work you need to have the sysrq-key enabled in the kernel. (CONFIG_MAGIC_SYSRQ)
You can check if it is enabled by typing 'ls /proc/sys/kernel/sysrq' if it's there, it's enabled.
Thanks to Mischa for pointing this out.
I found out about this here:
BY BRUNO (http://www.brunolinux.com/01-First_Things_To_Know/Skinny_Elephants.html)

[outofnicks]

Is this preferable to a hard shutdown? That is, holding the power button in on my Dell tower until it powers down--?

[xyz]

I think ANYTHING is better than a hard shutdown!
The "Raising Skinny Elephants Is Utterly Boring" allows for gradual 'shutdown'.

[kackler]

run the command "shutdown -r now" to reboot or "shutdown -h now" to power down completely.

[dbott67]

run the command "shutdown -r now" to reboot or "shutdown -h now" to power down completely.

As the original poster mentions:
If your system doesn't react at all, you are totally stuck, and even Ctrl+Alt+backspace gives nothing, try and 'save' the following phrase somewhere in your mind

If you're system is locked/frozen/stuck, you won't be able to open a terminal...

[ajm2005]

:)

[flargen]

I prefer to use alt + sysrq + k to kill all processes on the current terminal. It is especially useful if the X server dies and alt + ctrl + backspace doesn't work, because it allows you to log in again without restarting you computer.

[xyz]

alt + sysrq + k
Just wondering if that wouldn't be a bit drastic?

[mdowney]

Is there any way to do this with a Mac keyboard? I don't have a SysRq key.

[outofnicks]

My Macs don't have Ubuntu so don't know if this would work but the F13 key is in the same location, and also is labeled "Print Screen" as on the PC keyboard. But on my 97-key USB Mac keyboard, which you may have, that block of keys doesn't exist. There is a "help" key to the right of the F12 key, which may also work? Or possibly this is a PC-only thing?

[xyz]

Is there any way to do this with a Mac keyboard? I don't have a SysRq key.
Well I don't have a Mac so...
Mac OS X keyboard shortcuts (http://docs.info.apple.com/article.html?artnum=75459)
Sorry if you already know about this but you may find what you need there.
What about what "outofnicks" suggested?
Let us know...

[mdowney]

Not really sure, its a USB Mac keyboard, they standard 103 key one. I think the Mac shortcuts will only work in Mac OS X. I have not had a chance to try the F13 combo, yet. Next time I get a hardlock in X I will try it.

[tenghoward]

Is this type of shutdown will result data lost? If so, maybe I need to use my backup copy if I use this method.

[xyz]

Is this type of shutdown will result data lost? If so, maybe I need to use my backup copy if I use this method.
I have used it several times and never lost anything. Just wait 15-20 seconds between each keystroke as a precaution.
Good day!

[drphilngood]

Thanks for sharing this, xyz.

[outofnicks]

Next time I get a hardlock in X I will try it.

All I need is to have several OpenOfficedocs, a bunch of big pics in The Gimp, Firefox and Thunderbird open at the same time--that does it :rolleyes: ,

[xyz]

Thanks for sharing this, xyz.
You're welcome.

[mozkill]

I usually reboot using the command "init 6" . is there anything wrong with doing it that way?

[fraenhawk]

moz: As was stated already, the point of this is if your computer is not responding. If it's not responding, how/where are you going to type "init 6" anywhere?

xyz: I'll definitely have to keep this in mind, although I have to say I've only really been in a situation this would help with once that I can remember.

[xyz]

fraenhawk..knock on wood!
...I've only really been in a situation this would help with once that I can remember.
Reply With Quote
...and the one and only time you may be in that situation...well that's when you'll need to remember it. It's good to have that solution at hand when -and IF- you need it.

[rfdeshon]

Thanks for this, my edgy install locks up every couple days. This is a lot better than hard reseting my laptop every time. Does anyone else have problems with X after an upgrade from Dapper to Edgy where the keyboard will stop responding and no new applications will launch but everything else seems to be running?

[ltk5]

hm... interesting. Would have to try it, everything is better that just Power Off.:o

[outofnicks]

Having forgotten about this trick, or just failing to write it down somewhere, I've used Ctl-Alt-Delete which simply logs me out so I can log in for a fresh start. Anything wrong with this?

update:
If your system doesn't react at all, you are totally stuck, and even Ctrl+Alt+backspace gives nothing,
oops, never mind...

[durand]

um...what about ctrl+alt+f1(etc)

[of_darkness]

Have had several hardlocks so i tried the above keys in the sequens posted n then evry other key on the keybord but*too no effect at all.. kubuntu edgy n a swedish*logitech wireless keybord..whith swedish key mapp layout..

[firstc624]

i can't ge this to wrok even when not in a hard lock. i have a laptop and when it is actually running i get a print screen image

[xyz]

um...what about ctrl+alt+f1(etc)
I'll have to try next time but I have a feeling even that wouldn't work when totally stuck.

of_darkness
I sure wish I could understand why a Swedish keyboard layout would prevent this from working? What would then be the SysRq key equivalent?

[durand]

it doesnt...

[Nonno Bassotto]

For the skinny elephants to work you need to have the sysrq-key enabled in the kernel.

is it enabled by default in the Ubuntu kernel? When I type

ls /proc/sys/kernel/sysrq

I just get

/proc/sys/kernel/sysrq

[muguwmp67]

My solution to the reboot issue was reconfiguring my power button.

Preferences>Power Management
General tab
change the action when the power button is pressed.

This performs a clean (I think) shut down when I press the power button. None of that hard shutdown stuff now. You won't want to do this if you have a power button on your machine that is susceptible to being pressed by accident, but it works for me.

[xyz]

This performs a clean (I think) shut down when I press the power button.
I have no idea if this does an OKish shutdown.

For the other folks, I'll redirect you to Tony Luck's site (http://developer.osdl.org/dev/robustmutexes/REPOS/fusyn.hg/?cmd=file;filenode=32d0a5eb8f92fa9221a6311440ffafb c042e510b;file=Documentation/sysrq.txt) because it is explained much better/ more precisely than I could.
Let us know if this worked for you! Thx.

[xyz]

Please pay attention to this:
PS: If your filesystem is Ext3 or ReiserFS and on reboot it wants you to do a filesystem check, don't touch any key when it asks you to press "Y" and let it recover the journal automatically.

NOTE: For the skinny elephants to work you need to have the sysrq-key enabled in the kernel. (CONFIG_MAGIC_SYSRQ)
You can check if it is enabled by typing 'ls /proc/sys/kernel/sysrq' if it's there, it's enabled.
Thanks to Mischa for pointing this out.
It's been added to the original post.

[n8bounds]

This is from source docs:

http://lxr.linux.no/source/Documentation/sysrq.txt

[xyz]

Hi Gutsy Users,

Does this work for you? Does for me.

[Endolith]

I just used this for the first time. I'm in Gutsy, and it worked without changing anything in the kernel.

My computer locked up about two hours ago. I saw from the system monitor applet that the memory and swap space were maxed out, and I couldn't open virtual terminals or anything. I went to bed, expecting it to solve itself after a while. I came back now and it was still locked up.

You should really note Alt+SysRq+F, though, which kills the process that's using the most memory. That got me back into GNOME, but things weren't working right anymore. The keyboard was completely dead, and the window manager wasn't behaving correctly. I looked around to see if there was any unsaved data and then did these steps. It worked. Thanks!

[joopbraak]

NOTE: For the skinny elephants to work you need to have the sysrq-key enabled in the kernel. (CONFIG_MAGIC_SYSRQ)
You can check if it is enabled by typing 'ls /proc/sys/kernel/sysrq' if it's there, it's enabled.

It's actually like this:

You can check if it is enabled by typing
cat /proc/sys/kernel/sysrq
if the command returns "1" the sysrq-key is enabled.

If it returns "0" you can enable it with
echo 1 > /proc/sys/kernel/sysrq