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Date: Fri, 21 Feb 2003 14:25:30 -0500 (EST)
From: "Richard B. Johnson" <root@chaos.analogic.com>
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To: nataraja kumar <hainattu@yahoo.com>
cc: linux-kernel@vger.kernel.org
Subject: Re: A question on kernel stack 
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On Fri, 21 Feb 2003, nataraja kumar wrote:

> hi,
> my apologies if i am wrong. please let me know
> why does kernel use kernel stack when process jumps
> from user mode to kernel mode. why can't user stack
> be used ?
> 
> nattu.

Because if a user-stack was used, any user could crash the kernel
and take down the system.

main()
{
    __asm__ __volatile__("movl	$0x08, %esp\n");
                     /* Only enough stack to push 0 and call exit() */

    exit(0);     /* Ultimately a sys-call */
}



Cheers,
Dick Johnson
Penguin : Linux version 2.4.18 on an i686 machine (797.90 BogoMips).
Why is the government concerned about the lunatic fringe? Think about it.


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