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Re: modules

To: deepakyadav@xxxxxxxxx
Subject: Re: modules
From: Arun Sharma <adsharma@xxxxxxxxxxxxxxx>
Date: Sun, 8 Oct 2000 09:38:14 -0700
Cc: linux-india-programmers <linux-india-programmers@xxxxxxxxxxxxxxxxxxxxx>
In-reply-to: <200010090015.e990Fha27286@del1.vsnl.net.in>; from deepak2000@softhome.net on Sun, Oct 08, 2000 at 07:12:42PM +0500
References: <200010090015.e990Fha27286@del1.vsnl.net.in>
User-agent: Mutt/1.2i

On Sun, Oct 08, 2000 at 07:12:42PM +0500, nikkie21 wrote:
> hi
> i want to know that why we require special function   put_user   while
> copying data from kernel data segment  to user data segment.

So that if the user passes a bad pointer, the kernel doesn't fall on
its face. It used to do "verify_area" before dereferencing the pointer,
but in recent kernels, the verification is done using the CPU's MMU.
(Linux device drivers, Rubini, p 398).

	-Arun

References:
- modules
  - From: nikkie21

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