linux-kernel - Re: [Patch] Elf loader crash while zero-filling .bss

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Message-ID: <20080211185344.GA25510@uranus.ravnborg.org>
Date:	Mon, 11 Feb 2008 19:53:44 +0100
From:	Sam Ravnborg <sam@...nborg.org>
To:	Abel Bernabeu <abelbg@...rp.com>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [Patch] Elf loader crash while zero-filling .bss

On Mon, Feb 11, 2008 at 07:27:35PM +0100, Abel Bernabeu wrote:
> I've finally found a solution for the crash in load_binary_elf I
> reported last week:
> 
> http://lkml.org/lkml/2008/1/30/171
> 
> The attached patch solves my problem, but please test it yourself...
> 
> set_brk(start, end) allocs just page aligned regions (by "colapsing"
> both extremes to the start of the page in which they lay)... That
> means than even if both pointers are not equal there are still some
> chances that set_brk has allocated no space at all because
> ELF_PAGEALIGN(elf_bss) != ELF_PAGEALIGN(elf_brk).

What architecture was this?
Most architectures align .bss properly but it seems arm does not
and I guess this is needed.

As .bss was empty? in your case you did not trigger
any alignmnet by linker due to largest member in section => boom.

I do think your patch paper over the real bug.

	Sam
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