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From: "Luís Henriques" <lhenriques@criticalsoftware.com>
To: Anton Altaparmakov <aia21@cam.ac.uk>, <linux-kernel@vger.kernel.org>
Cc: <linux-kernel@vger.kernel.org>
Subject: Re: copy to suer space
Date: Tue, 20 Nov 2001 17:08:52 +0000	[thread overview]
Message-ID: <200111201714.fAKHEc276467@criticalsoftware.com> (raw)
In-Reply-To: <5.1.0.14.2.20011120165440.00a745b0@pop.cus.cam.ac.uk>
In-Reply-To: <5.1.0.14.2.20011120165440.00a745b0@pop.cus.cam.ac.uk>

> I don't think what you are trying to do is possible. Even if you somehow
> managed to write over the code segment of a user space process (which I
> very much doubt would be possible as I assume the memory is mapped
> read-only)

Is there a way to solve this problem? To temporarly turn it read/write?

>, as soon as the kernel pages out (i.e. discards!) some portion
> of the executable due to memory shortage your changes would be lost, since
> the paging back into memory would happen by reading the executable back
> from disk, which would mean it would read the unmodified code into
> memory...

When I'm modifing the code, I'm sure that the page is in memory because my 
code is called from the user space, in the exact location where I want to 
change it (with a breakpoint interruption...)

The point is that I can't write to the memory location I want... How do I 
solve this?

-- 
Luís Henriques

  reply	other threads:[~2001-11-20 17:14 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <Pine.LNX.4.31.0111201637420.13674-100000@mail.deis.isec.pt >
2001-11-20 17:02 ` copy to suer space Anton Altaparmakov
2001-11-20 17:08   ` Luís Henriques [this message]
2001-11-20 18:41     ` Andreas Dilger
2001-11-20 18:44       ` Luís Henriques
2001-11-20 18:58         ` Hua Zhong
2001-11-20 19:39         ` Andreas Dilger
2001-11-21  0:06           ` Mike Fedyk
2001-11-21 10:52             ` Luís Henriques
2001-11-23 13:14               ` Juan Quintela
2001-11-23 14:35                 ` Luís Henriques
2001-11-23 23:53                   ` H. Peter Anvin
2001-11-20 17:37   ` Anton Altaparmakov
2001-11-20 17:53     ` Luís Henriques
2001-11-20 18:18       ` Nick LeRoy
2001-11-22 18:51       ` Andreas Bombe
2001-11-20 18:09   ` Luís Henriques
2001-11-21 14:37 Joerg Pommnitz
     [not found] <sbfa4d3a.051@MAIL-SMTP.uvsc.edu>
2001-11-21 10:49 ` Luís Henriques
  -- strict thread matches above, loose matches on Subject: below --
2001-11-20 16:40 Luis Miguel Correia Henriques

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