From: Paulo Marques <pmarques@grupopie.com>
To: Vegard Nossum <vegard.nossum@gmail.com>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] kallsyms: fix potential overflow in binary search
Date: Wed, 14 May 2008 12:44:13 +0100 [thread overview]
Message-ID: <482AD08D.7070206@grupopie.com> (raw)
In-Reply-To: <20080513200736.GA17909@damson.getinternet.no>
Vegard Nossum wrote:
>>From 61b840f071e496f632fcc293f5435428cfc98844 Mon Sep 17 00:00:00 2001
> From: Vegard Nossum <vegard.nossum@gmail.com>
> Date: Tue, 13 May 2008 10:20:27 +0200
> Subject: [PATCH] kallsyms: fix potential overflow in binary search
>
> This will probably never trigger... but it won't hurt to be careful.
Not "probably", this will never trigger _period_. If you ever have more
than 2^31 symbols in the kernel's kallsyms table you'll have worse
problems to worry about than the binary search overflowing.
So, I don't think it is worth this des-optimization at all...
> http://googleresearch.blogspot.com/2006/06/extra-extra-read-all-about-it-nearly.html
>
> Signed-off-by: Vegard Nossum <vegard.nossum@gmail.com>
> ---
> kernel/kallsyms.c | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
> index 6fc0040..38fc10a 100644
> --- a/kernel/kallsyms.c
> +++ b/kernel/kallsyms.c
> @@ -176,7 +176,7 @@ static unsigned long get_symbol_pos(unsigned long addr,
> high = kallsyms_num_syms;
>
> while (high - low > 1) {
> - mid = (low + high) / 2;
> + mid = low + (high - low) / 2;
> if (kallsyms_addresses[mid] <= addr)
> low = mid;
> else
--
Paulo Marques - www.grupopie.com
Dear aunt, let's set so double the killer delete select all.
-- Microsoft voice recognition live demonstration
next prev parent reply other threads:[~2008-05-14 11:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-13 20:07 [PATCH] kallsyms: fix potential overflow in binary search Vegard Nossum
2008-05-14 11:44 ` Paulo Marques [this message]
2008-05-14 12:22 ` Pekka Enberg
2008-05-14 14:24 ` Paulo Marques
2008-05-14 15:31 ` Vegard Nossum
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