linux-kernel - Re: brk randomization breaks columns

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Message-ID: <20080205180519.GA1525@elf.ucw.cz>
Date:	Tue, 5 Feb 2008 19:05:19 +0100
From:	Pavel Machek <pavel@....cz>
To:	Jiri Kosina <jkosina@...e.cz>
Cc:	kernel list <linux-kernel@...r.kernel.org>,
	Ingo Molnar <mingo@...e.hu>,
	Abel Bernabeu <abel.bernabeu@...il.com>,
	Hugh Dickins <hugh@...itas.com>,
	Arjan van de Ven <arjan@...radead.org>
Subject: Re: brk randomization breaks columns

Hi!

> diff --git a/mm/mmap.c b/mm/mmap.c
> index 8295577..1c3b48f 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -241,7 +241,7 @@ asmlinkage unsigned long sys_brk(unsigned long brk)
>  
>  	down_write(&mm->mmap_sem);
>  
> -	if (brk < mm->end_code)
> +	if (brk < mm->start_brk)
>  		goto out;
>  
>  	/*

Sorry, I now tested the patch. It looked good to my untrained eyes,
but upon testing it on columns:

...
personality(PER_LINUX)                  = 4194304
geteuid()                               = 1000
getuid()                                = 1000
getgid()                                = 1002
getegid()                               = 1002
brk(0x8054098)                          = 0x922d000
--- SIGSEGV (Segmentation fault) @ 0 (0) ---

...it should have said -EINVAL or something like that.

									Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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