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From: Andrea Arcangeli <andrea@novell.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Arjan van de Ven <arjanv@redhat.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@osdl.org>
Subject: Re: heap-stack-gap for 2.6
Date: Wed, 29 Sep 2004 17:44:37 +0200	[thread overview]
Message-ID: <20040929154437.GD22008@dualathlon.random> (raw)
In-Reply-To: <1096467886.15905.33.camel@localhost.localdomain>

On Wed, Sep 29, 2004 at 03:24:46PM +0100, Alan Cox wrote:
> As the man page says
> 
> "Use of this option is discouraged."

and as a matter of fact the vast majority of mmaps executed by databases
with vlm are using MAP_FIXED ;)

I'm not saying databases themself are going to break with topdown, I'm just saying
there are applications out there making heavy use of MAP_FIXED, no
matter if the above manpage says it's discouraged. depending on
applications not to use it, isn't reliable and it's prone to break
randomly at runtime with topdown, this is my _only_ point, and it's a
tangible fact as far as I can tell (not a purerly theoretical issue like
the set_pte not being exceuted in asm).

If you want to make your kernel really safe, then disable MAP_FIXED and
return -EINVAL, then I agree it will be safe.

  reply	other threads:[~2004-09-29 15:45 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-09-25 16:22 heap-stack-gap for 2.6 Andrea Arcangeli
2004-09-25 23:57 ` Rik van Riel
2004-09-26  0:40   ` Andrea Arcangeli
2004-09-27  8:09 ` Arjan van de Ven
2004-09-27 13:09   ` Andrea Arcangeli
2004-09-28 19:43     ` Arjan van de Ven
2004-09-28 22:19       ` Andrea Arcangeli
2004-09-29  6:05         ` Arjan van de Ven
2004-09-29 14:11           ` Andrea Arcangeli
2004-09-29 14:24             ` Alan Cox
2004-09-29 15:44               ` Andrea Arcangeli [this message]
2004-09-29 14:25             ` Arjan van de Ven
2004-09-29 14:53               ` Andrea Arcangeli
2004-09-29 15:01                 ` Arjan van de Ven
2004-09-29 15:40                   ` Andrea Arcangeli
2004-09-28  6:25 ` Hui Huang
2004-09-28 14:19   ` Andrea Arcangeli
2004-09-29  8:42     ` Hui Huang
2004-09-29 14:23       ` Andrea Arcangeli
2004-09-29 22:01         ` Hui Huang
2004-10-12  0:51           ` Andrea Arcangeli

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