linux-kernel - Re: [PATCH] FDPIC: Ignore the loader's PT_GNU

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Message-ID: <20090711213018.GA1425@ucw.cz>
Date:	Sat, 11 Jul 2009 23:30:18 +0200
From:	Pavel Machek <pavel@....cz>
To:	David Howells <dhowells@...hat.com>
Cc:	Mike Frysinger <vapier.adi@...il.com>, rgetz@...ckfin.uclinux.org,
	lethal@...ux-sh.org, gerg@...inux.org,
	uclinux-dist-devel@...ckfin.uclinux.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] FDPIC: Ignore the loader's PT_GNU_STACK when
	calculating the stack size

On Thu 2009-07-09 11:59:11, David Howells wrote:
> Pavel Machek <pavel@....cz> wrote:
> 
> > > i really dont think this is realistic.  there is exactly one ldso that
> > > everyone uses under FDPIC ELF, and it needs a very minuscule stack.
> > 
> > Not very realistic; but that argues that the patch is NOP.
> >
> > And if it _is_ realistic, the patch adds a bug.
> 
> No, it doesn't.  The problem is that the loader, when it is linked, is given a
> sillyly large default stack size, and this causes the application to be given a
> much larger stack than is strictly necessary - a stack that is drawn from a
> limited pool of non-pageable RAM and that must be allocated as a contiguous
> lump.

Fix the loader to only request as big stack as it needs?
									Pavel
-- 
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