Linux Lock-up

[a_yeap]

I'm using Redhat Linux 7.1, with KDE and I have problems with the screen locking up...

I thought Linux is supposed to be extremely stable but frequently, my computer just freezes, and nothing is happening (ie nothing reading to/from the HD)...meaning I have to just turn the power off...

Is there any way to manually shut down the computer...I read another thred entitled 'How to shutdown Linux' and I did try those out when Linux froze again, but none of them worked...I tried the Ctrl-Alt-backspace and the Ctrl-Alt-F1/F6 and still nothing happened...

Nothing was responding so I can't access the terminal to type
init 0

I know Windows has the Task Manager...I wonder if KDE has it too...and also, could someone explain WHY it happens...I have plenty of swap space and 128Mb of RAM

[ken257]

The problem is that the GUI takes control of your keyboard and mouse so that if the gui locks you loose the ability to input. Underneath though Linux is probably still going strong you just can't access it. This is where telnet comes in handy. From another box you can telnet in and kill the offending process or just plain shut the machine down.

Also try ctrl/alt/backspace and see if that will force quit the gui for you.

I am running SuSE 7.2 it has newer versions of everything and I have not had any lockups at all, very very stable. I was never thrilled with RH7.1 or Mandrake 7.2 they were very betaish for me.

[klosters64a]

Cntrl-Alt-Backspace kills the X-Server. This can be a lifesaver! If you have Mandrake configured to boot into a GUI login prompt, this particular three fingered salute isn't much good. Linux HATES the "real" three-fingered salute, and it hates the reset button even more. Sooner than later you'll see that dreaded "system halted," or worse "kernel panic" mssage while you reboot. Then the machine just sits there......

[a_yeap]

Yes, I already read about the ctrl-alt-backspace trick...but it didn't work when I tried it...

I've had the 'kernel panic' message twice already...I just want to shut X-server, or the whole OS, down when it stops responding...didn't the Linux geniuses plan for some way for the user to shut the computer down when it stops responding...I thought Microsoft were a bunch of idiots but even they thought of the 'task manager'...

[klosters64a]

Hoo boy, the "kernel panic" and "system halted" final messages during boot just wreck my day. The good old classic three finger salute will sometimes successfully reboot your box. As will the "reset" button. Linux doesn't like Cntrl-Alt-Del, and it really doesn't like the reset button. Hitting the reset button results in the need for a complete OS reinstall about one in six times.

"Bah, humbug" say the Linux old salts, "you can fix anything from the CLI," they insist. Sure, maybe they can!

[David]

oh dear, looks like trouble.

Telnet is ok but can be tricky ie. no second PC, no netwrok, no modem, etc. I think you also need a telnet host daemon, and you can't log in as root.

<Ctrl><alt><BS> can in some cases be ignored by X. this is, however, quite rare as you have to put ity in your XF86Config.

Ok try the following (in this order):

1. <Ctrl><alt><BS> can reboot or shutdown X (on my machine it reboots X)

2. <Ctrl><alt><F12> kills X.

3.If you've tried these, now this stuff gets a bit harder.

At the lilo boot prompt, when it says 'boot:' type:

linux single

(where linux is the name of your linux entry). This will NOT start X and will take you into a console mode. Sort out you config files or reinstall X or whatever, then type:

init 3

And pray to god (and Allah, and Yahweh and Buddha,...) that X works. Good luck

4. Failing that (oh crap your in trouble now) use a boot disk like tomsrtbt - www.toms.net/rb or some other rescue disk.
mount your hdd under /mnt and work on the config files or whatever


Unfortunately I have only ever used SuSE, Mandrake or Slackware and have no experience with red hat.

[mcrites]

If you have the magic sysrq compiled into your kernel do this:

alt+sysrq+s - this syncs the devices
alt+sysrq+u - this unmounts all devices
alt+sysrq+b - this reboots the system

You should be able to do this anywhere where something takes over the control devices and wont give it back. Like an above post, linux is different from the gui subsystems: Xfree86 and your favorite wm, most likely its a driver messing up, or sometimes even apps taking down the X Window system. The above sequence makes sure that you do not have to fsck since it umounts all devices and syncs data in the buffers.

[David]

...always wondered what Magic Sysrq did...

Do you not need to compile it into your kernel? Will the factory standard kernel include this?

[mcrites]

I am not sure what you mean by stock kernel. If that means from kernel.org, I dont think the option is selected by default. Just enable it and recompile and thats all there is to do, I believe its under testing or something like that.