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Date: Fri, 13 Feb 2004 10:33:55 -0800
From: "Martin J. Bligh" <mbligh@aracnet.com>
To: Andi Kleen <ak@suse.de>, Jamie Lokier <jamie@shareable.org>
cc: torvalds@osdl.org, mingo@elte.hu, benh@kernel.crashing.org,
       linux-kernel@vger.kernel.org, akpm@osdl.org, drepper@redhat.com
Subject: Re: [BUG] get_unmapped_area() change -> non booting machine
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--On Sunday, February 15, 2004 06:25:44 +0100 Andi Kleen <ak@suse.de> wrote:

> On Fri, 13 Feb 2004 03:26:04 +0000
> Jamie Lokier <jamie@shareable.org> wrote:
> 
>> Linus Torvalds wrote:
>> > One option is to mark the brk() VMA's as being grow-up (which they are), 
>> > and make get_unmapped_area() realize that it should avoid trying to 
>> > allocate just above grow-up segments or just below grow-down segments. 
>> > That's still something of a special case, but at least it's not "magic" 
>> > any more, now it's more of a "makes sense".
>> 
>> That reminds me.  What happens when grow-down stack VMAs finally bump
>> into another VMA.  Is there an unmapped guard page retained to segfault
>> the program, or does the program silently start overwriting the VMA it
>> bumped into?
> 
> In the standard kernel it silently overwrites, but in 2.4-aa there was a patch forever
> that adds a guard page.

Do you happen to remember the name of the patch? Hunting in Andrea's tree
isn't always easy ;-)

M.