Date: Sat, 11 Jul 2009 23:30:18 +0200
From: Pavel Machek <pavel@ucw.cz>
To: David Howells <dhowells@redhat.com>
Cc: Mike Frysinger <vapier.adi@gmail.com>, rgetz@blackfin.uclinux.org,
       lethal@linux-sh.org, gerg@uclinux.org,
       uclinux-dist-devel@blackfin.uclinux.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] FDPIC: Ignore the loader's PT_GNU_STACK when
	calculating the stack size
Message-ID: <20090711213018.GA1425@ucw.cz>
References: <20090709101930.GJ10937@elf.ucw.cz> <20090704024606.GE1345@ucw.cz> <20090701120814.30741.10146.stgit@warthog.procyon.org.uk> <24530.1247050900@redhat.com> <20090704033429.GA1799@ucw.cz> <8bd0f97a0907081148vc716eeepfdaf8178b1ecbce1@mail.gmail.com> <24280.1247137151@redhat.com>
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On Thu 2009-07-09 11:59:11, David Howells wrote:
> Pavel Machek <pavel@ucw.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
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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