Re: What dose 'general protection fault: 0000' mean?

[Gilad Ben-Yossef <gilad@benyossef.com>]

On Tue, 2002-06-11 at 08:36, Wang Hui wrote:


> > >Code: 8b 02 8b 55 08 89 02 8b 55 0c 8b 42 04 8b 55 08 89 42 04 8b
> > ><0> Kernel panic: Aiee, killing interrupt handler!
> > >In interrupt handler - not syncing
> > >
> > >==================================================
> > >
> > >I am a newbie to linux kernel hacking.  I dont know how to find out
> > >where is the fault code.  :(  Could anyone give me some hints???

> > it seems that you remove the  process that handles this
> > interupt (perhaps by using kfree). or remove the module,
> > while the kernel still think that the handler is still there...

In the /scripts directory of the Linux tree there is a small utility
that can help you grok these oopses. It is called 'ksymoops'.

> To realize the function 1, I use this tricks: I modified all the kernel's
> active network device's dev->hard_start_xmit function pointer to be my own
> function named as 'my_output_handler', and backuped the original
> 'dev->hard_start_xmit' funtion pointer witch will be called inside
> 'my_output_handler' as to send out the modified data.

Suggestion: don't change kernel primitives like this. Instead write your
code as a Netfilter/iptables module. IMHO it's more of the Right
Thing(tm) and will save you a bunch of headaches...

> ethernet device which is a realtek 8139 network card, I got kernel panic.
> I dont know what to do with it?  I guess this panic is due to something
> difference between loopback network device and the real network device
> drivers. But I dont know exactly what is wrong, or say, that what should I
> do to avoid this panic?  Any rules to write safe code here?

Only 1 rule really - what ever happens, under ANY circumstances, never
ever go chasing after the ship's cat. Remember: "In Kernel space, no one
can hear you scream." :-)

Gilad.

-- 
Gilad Ben-Yossef <gilad@benyossef.com>
http://benyossef.com
"Hail Eris! All Hail Discordia!"