Dealing with crashes

[kbunt]

Hello,
I was wondering what your opinions are on crashes and how you react to them in Linux.

I am used to the "Windows way" of CTRL-ALT-DEL and then going to the Task Manager and cancelling the process. Sometimes, you just don't want to reboot the computer and can get out of a crash from closing applications or killing an app that is causing the problem.

But, how do you figure out which app is causing the problem in Linux and what can you do to deal with a crash or if your system freezes up?

I can't recall exactly but I think there are command line methods of discovering which processes are running and methods for 'killing' a process or application. Is this what you do?

I think each app is assigned a unique PID and you can kill a process/app (after becoming root?) by a command such as kill 'PID #' and the corresponding process/task will be terminated, right? How does one determine that process/task is the culprit? By going to the command line and finding out which is taking up the most processing resources? Would using the command, 'top' accomplish this?

What if your computer is so frozen, that you can't get to the command line? Say, your mouse (cursor) is frozen? Anything you can do save rebooting?

[garry_3peace]

Re: Dealing with crashes

Hello I am newbie too...

Maybe we can use Ctrl+Esc or maybe Ctrl+Alt+Esc?? Because it will show a somekind like Task Manager.
I ever read it somewhere, but my computer never hang in kubuntu, so I am not sure, whether it is work or not. hehe.
:P

[dibl]

Re: Dealing with crashes

But, how do you figure out which app is causing the problem in Linux and what can you do to deal with a crash or if your system freezes up?

Kubuntu normally pops up a crash notification that tells which app crashed. There's also a log of crashes at /var/logs/crash (I think that's the file location -- you might want to check it out because I'm relying on my senile old memory at the moment ... ).

I can't recall exactly but I think there are command line methods of discovering which processes are running and methods for 'killing' a process or application. Is this what you do?

I've only used Linux for a year and haven't memorized very many bash commands. Depending on your taste, here are two approaches to dealing with it:

1. Buy a book, and keep it handy so you can look up bash commands. Beginning Ubuntu Linux, by Keir Thomas, is a good one.

2. Alt-F2

kdesu ksysguard

and click the "Processes" tab. Scroll down to the one that is having a problem, and use the "kill" button at the lower right of the window.

I think each app is assigned a unique PID and you can kill a process/app (after becoming root?) by a command such as kill 'PID #' and the corresponding process/task will be terminated, right? How does one determine that process/task is the culprit? By going to the command line and finding out which is taking up the most processing resources? Would using the command, 'top' accomplish this?

You've got it about right. If an app crashes, there may or may not be a running process post-crash -- sometimes Linux kills it off when it crashes. In other words, a lot of times all you get is the crash notification, and then it's history for that process, and you won't find anything running related to the crashed app.

What if your computer is so frozen, that you can't get to the command line? Say, your mouse (cursor) is frozen? Anything you can do save rebooting?

Great questions!

OK, remember this little mnemonic:

Raising Skinny Elephants Is Utterly Boring


Whenever you encounter a "locked up" system (i.e. Ctrl-Alt-Backspace will NOT restart the X server), which hopefully is rare (I've had it about 4 times in a year), it isn't really locked up, only the video part of it is, and you can perform a graceful shutdown on it (with no screen feedback, of course), by holding down the Ctrl-Alt-SysRq keys, and pressing in sequence RSEIUB.

SysRq is the key known in DOS/Windows as "PrtScrn", along the top row of keys.

[eriefisher]

Re: Dealing with crashes

CTRL-ESC---------Gives you the "task manager"
CTRL-ALT-ESC--------Changes your curser, Click on an app and kill it.
CTRL-ALT-Backspace------Restarts the x server for full lock up

eriefisher

[Rog131]

Re: Dealing with crashes

Maybe these help:

Controlling runaway processes on Linux
http://rudd-o.com/archives/2007/08/0...sses-on-linux/

Sometimes, buggy memory hogs can choke your machine. Here, two tricks: one to recover from a memory choke, another to prevent memory chokes forever.

- Misbehaving application frozen?

- Application choking your machine?

- A last-resort trick to recover your machine from the brink of death

- A definitive cure to runaway applications

LinuxLogFiles
https://help.ubuntu.com/community/LinuxLogFiles

Introduction

One of the things which makes GNU/Linux a great operating system is that virtually anything, and everything happening on, and to the system may be logged in some manner. This information is invaluable to using the system in an informed manner, and should be one of the first resources used in trouble-shooting system, and application issues. The logs can tell you almost anything you need to know, so long as you have an idea where to look first.