How to debug Kernel Panic

murphaph

Hi all,
I run Linux Mint 11 on an acer laptop and had a lot of trouble getting the wireless to work. I eventually found a solution that involved compiling a driver from the manufacturer of the wireless chipset etc. and it all worked really well for 3 weeks or so (using wicd).

Now anytime I try to connect to my wireless network I get a kernel panic and the computer locks up completely (to my eyes). Somrthing must have changed to conflict with the wireless I think. How can I begin to debug this? Which error logs should I be starting with?

Cheers!

Khannie

Disaster zone. I think you're pretty screwed. When the kernel panics, it just dumps a load of stuff to the tty, but I'm 99% sure it doesn't write any logs (because it's in a panic ).

murphaph

Cheers. If I can't find a solution I'll have to accept defeat and just use this laptop with Ethernet. I have installed and configured a load of development software and I really don't feel like a fresh install and starting all over again (again). Wireless is still an Achilles heel for Linux and is definitely stopping its wider adoption (had the same trouble on a mate's Acer laptop.

Johnboy1951

murphaph wrote: »

Cheers. If I can't find a solution I'll have to accept defeat and just use this laptop with Ethernet. I have installed and configured a load of development software and I really don't feel like a fresh install and starting all over again (again). Wireless is still an Achilles heel for Linux and is definitely stopping its wider adoption (had the same trouble on a mate's Acer laptop.

Rather a broad statement

What wireless chip is it?
What driver?

Maybe all is wrong is the driver you are using is corrupted or now incompatible after something was updated ......

murphaph

Johnboy1951 wrote: »

Rather a broad statement

Broad yes but a quick Google of "Linux wireless" reveals it's a massive problem area for the OS still. Linux can't be considered to work out of the box on a laptop if the wireless doesn't. It'll (sadly) hinder Linux uptake so long as it remains an issue.

Johnboy1951 wrote: »

What wireless chip is it?

It's a Ralink 2860.

Johnboy1951 wrote: »

What driver?

The one from Ralink, with a couple of mods performed according to this thread.

Johnboy1951 wrote: »

Maybe all is wrong is the driver you are using is corrupted or now incompatible after something was updated ......

Hmmm, but how to debug is the problem. I haven't performed any auto updates or anything like that (had enough problems with Auto Updates breaking thinks in Ubuntu). Software wise I have not installed any new programs but have installed plugins for things like Eclipse, though the kernel panics as soon as I attempt to connect through wireless, even when no user apps are running.

Johnboy1951

You seem to be equating problems in your install of Ubuntu with Linux in general.
I don't use Ubuntu so cannot comment on that aspect.

I do know that there are drivers and firmware available to me for the rt2860 if required in this Linux install.

There is no general problem that I am aware of with that chipset.

On Friday last I installed PCLinuxOS on a Toshiba Satellite without problems ..... that has the RTL8188CE chip. It was on line without any input from me. The firmware for the 2860 was available for use on that liveCD, so if it had a 2860 chip there would not have been a problem either.

As I said above ..... your statement was rather broad and not necessarily the experience of others using Linux.

regards.

murphaph

Johnboy1951 wrote: »

You seem to be equating problems in your install of Ubuntu with Linux in general.
I don't use Ubuntu so cannot comment on that aspect.

I do know that there are drivers and firmware available to me for the rt2860 if required in this Linux install.

There is no general problem that I am aware of with that chipset.

On Friday last I installed PCLinuxOS on a Toshiba Satellite without problems ..... that has the RTL8188CE chip. It was on line without any input from me. The firmware for the 2860 was available for use on that liveCD, so if it had a 2860 chip there would not have been a problem either.

As I said above ..... your statement was rather broad and not necessarily the experience of others using Linux.

regards.

Erm, is that it? I thought you were going to help debug the problem when you asked for chipset specifics. If not, then please don't clutter up the thread, thx.

humbert

Have you looked in \var\log\messages? klogd will write kernel debug messages there but I'm not exactly sure if that will happen during a panic. You could also use modprobe to see if the module is loaded and if not use modprobe to insert it and see if that caused the problem.

You could also use iwconfig and iwlist to test the driver and see exactly where the problem is originating.


On a more defensive note, I'd doubt that ralink chipset would work out of the box on most OS. But I'd generally agree that wifi is a long way from perfect on linux.

murphaph

Thanks Humbert, just reading this now and dog tired. Will take a look tomorrow. The chipset worked fine under W7 pro before I wiped it off the hard drive

Ralink, to be fair to them, have gone much further than many hardware manufacturers and have actually provided open source drivers for Linux-it was one of these that I had to modify before compiling that actually got wireless on the laptop working for the first time (I was delighted and it seemed totally robust, automatically connecting after hibernate etc, the works).

Hopefully I can resurrect this behaviour.

cian1500ww

Might be worth a try: http://wireless.kernel.org/en/users/Download

I use there b43 driver as opposed to the one that comes with Ubuntu