linux-kernel - Re: [PATCH -mm] Don't truncate /proc/PID/environ at 4096 characters

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Message-ID: <46F3CB76.3080304@moving-picture.com>
Date:	Fri, 21 Sep 2007 14:47:34 +0100
From:	James Pearson <james-p@...ing-picture.com>
To:	Arvin Moezzi <moezzia@...il.com>
CC:	linux-kernel@...r.kernel.org, aarapov@...hat.com,
	akpm@...ux-foundation.org, hpa@...or.com
Subject: Re: [PATCH -mm] Don't truncate /proc/PID/environ at 4096 characters

Arvin Moezzi wrote:

> I think that's not true. 'count' is changing through the iteration.
> The difference in the mem_read():
> 
> * while (count > 0) {
> *     int this_len, retval;
> *
> *      this_len = (count > PAGE_SIZE) ? PAGE_SIZE : count;
> *      retval = access_process_vm(task, src, page, this_len, 0);
> *
> *      ...
> * }
> 
> is the fact, that this_len = min(PAGE_SIZE, count) is in the
> iteration block, hence retval <= this_len <= count in each iteration
> step. So this is ok. But IMHO in your code 'retval' may be bigger than
> 'count' in the last iteration of the block, because 'max_len' is fix
> through your iteration but 'count' is changing. Or am i missing
> something?

Yes, you are correct ...

Thanks

James Pearson
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