Subject: RE: [hackers-il] What is the meaning of 100 Mb/s connection?

From: Chen Shapira <[email-masked]>
Date: Tue, 20 Feb 2001 14:03:07 +0200

> "Anything that can go wrong, will go wrong, while interrupts 
> are disabled. "
> 	-- Murphey's law of kernel programing.

The second law is that you can't debug it?

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From: Gilad Ben-Yossef <[email-masked]>
Date: Tue, 20 Feb 2001 14:28:02 +0200

> The second law is that you can't debug it?

Actually that's not true. The kernel "Ooppss" message is realy realy 
usefull. It gives you the stack, registers and code where you've done
something you shouldn't and it's usually quite easy to locate from that
the source code line where the problem manifested itself.

There's even a small utility that half automates this for you called 
ksymsoops.

Also, the "Magic SysReg" key can do wonders when you've managed to lock 
he kernel to some infinte loop to find out where you are (grab the EIP).
I think RedHat primal sin is that they've disabled this by default on 
they're distributions.

Then there's the kernel debuggers. (I know of two). There'yre hell to 
set up, but once you did it it really makes things simpler.

Gilad.

-- 
Gilad Ben-Yossef <[email-masked]>
http://benyossef.com :: +972(54)756701
"Anything that can go wrong, will go wrong, while interrupts are disabled. "
	-- Murphey's law of kernel programing.

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From: Alex Shnitman <[email-masked]>
Date: Tue, 20 Feb 2001 14:49:04 +0200

Hi, Gilad!

> I think RedHat primal sin is that they've disabled this by default on 

It was enabled in some versions, and AFAIR it was later disabled after
someone noted on BUGTRAQ that it's possible to use it to bypass the
console locking program (vlock I think). I haven't heard of anyone
actually using vlock (maybe some of the die-hard I-won't-use-X-
because-it-loads-my-system folks), but whatever.

-- 
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