How can I track down the cause of a freeze?

InfinityX · Guru Joined: 31 Jan 2004 Posts: 385

Occasionally my Gentoo box (Athlon XP, kernel 2.6.5-gentoo) will completely freeze, mouse, keyboard, everything. The only solution being a hard reset. It happens randomly, I can be playing a game, typing a document or just browsing.

It happened again just now, but strangely my WinXP box which my dad was using to browse could still access the internet (I've got Masquerading set up through a crossover cable), my modems lights would still be blinking.

After some earlier searches I'd heard that ACPI support in the kernel can be the source of many freezes, so I took it out and recompiled, and it still happens.

Where do I begin?

searcher · Apprentice Joined: 13 Mar 2003 Posts: 175 Location: NL

When your pc freezes, try to use ssh to login to the machine and see if anything still works. It might only be X freezing up on you. If this doesn't work you'll need a hard reboot to get back in, however not all is lost.

Depending on what system logger you use, you can find most stuff that happens to your pc in the /var/log directory. Look through the most recent logs for anything weird. If you're lucky you'll find out what went wrong before your pc froze. Chances are you won't be the only one experiencing this, so try searching the forum/google on any errors or warnings you got from the logs.

If this doesn't work you could increase the logging level to be more verbose in the logs; look to the manpage of your logger for more info on this.

~searcher
_________________
You are unique ... just like everyone else.

squeegy · Posted: Sun May 09, 2004 11:02 pm Post subject:

i had a box that had heat issues and it would randomly freeze. i reapplied thermal paste and reseated the heatsink everythign was fine after that.

InfinityX · Guru Joined: 31 Jan 2004 Posts: 385

Well I've never used ssh but have a fair idea of what it's about. Since my other computer can get on the Internet you're probably right about the X freezing thing.

I don't really know what to look for in /var/logs:

searcher · Apprentice Joined: 13 Mar 2003 Posts: 175 Location: NL

When your pc freezes get on your dad's winxp box, and use putty to log into your gentoo box. Make sure you have sshd running on your gentoo pc

InfinityX · Guru Joined: 31 Jan 2004 Posts: 385

Okay ssh is now running, and I've modified and tested my firewall and I can get in through my dads computer. But when the freeze next occurs how do I kill of X? Is it as simple as pkill X?

Ctrl-Alt-Backspace has never worked after a freeze unfortunately.

But now you've got me interested in ssh, could I use it to send files to and from my friends computers? I assume I would need a client for gentoo and they'd need a server like sshd?

*sorry for going OT with this*

searcher · Apprentice Joined: 13 Mar 2003 Posts: 175 Location: NL

InfinityX · Guru Joined: 31 Jan 2004 Posts: 385

Well it's been several days and still no freeze, but sshd is always running since it's so useful. It's just amazing setting an emerge going whilst at college.

Never thought it would take this long for it to crash, in Windows all I have to do is open an explorer window half the time

flindt · Posted: Sun Jun 06, 2004 7:42 am Post subject:

I've been seing the same problem (or at least very similar).
Every now and then (maybe once / 3 weeks uptime) my keyboard dies and X does not respond to mouse clicks, however, the mouse cursor is still moving.

I've been able to shut down X and restart it remotely (ssh), and then everything works fine - right until I log out of the ssh, then the new X dies completely.

Does anyone know why this is? Is the X killed together with the terminal because of the parent / child relations between processes ?

Vaughn · n00b Joined: 28 May 2003 Posts: 33

Yes.

How do you *normally* start X?
If it's with startx, well, then just use startx. If it's with [xkg]dm, then do a /etc/init.d/xdm restart.

That aside: To avoid having X (or any other app) die on you, there are two often used solutions.
1: Prepend the command line with nohup, like this: "nohup X &". It'll stop it from dying but you won't be able to control it either. (It's X, so that doesn't matter.)
2: Use screen. Think "textmode VNC" to understand what it does.

InfinityX · Guru Joined: 31 Jan 2004 Posts: 385

I migrated to X.org after another lockup and sure enough 13 hours in everything froze.

I immediately went to my dad's computer to try ssh, nothing, I couldn't even ping. Ctrl-Alt-Backspace didn't work, and ordinary things the keyboard LEDs didn't work. However it did respond to the sysrq key. The normal procedure of using sysrq+r to recover from an X crash didn't work (but then that particular shortcut never has), I was able to sync and unmount before rebooting.

Where do we go from here?