Message-ID: <1381249090.2081.240.camel@joe-AO722>
Subject: Re: [PATCH] core: Catch overflows in do_div() function
From: Joe Perches <joe@perches.com>
To: Anatol Pomozov <anatol.pomozov@gmail.com>
Cc: linux-kernel@vger.kernel.org, rdunlap@infradead.org
Date: Tue, 08 Oct 2013 09:18:10 -0700
In-Reply-To: <1381248622-27809-1-git-send-email-anatol.pomozov@gmail.com>
References: <CAOMFOmXfw2DkesOYip9VFDdUQgVN48qbJfuertPaSCz5aGdaeA@mail.gmail.com>
	 <1381248622-27809-1-git-send-email-anatol.pomozov@gmail.com>
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On Tue, 2013-10-08 at 09:10 -0700, Anatol Pomozov wrote:
> If second parameter passed to this function was 64 then it silently
> truncates to 32 bits. Catch such situation.
[]
> diff --git a/include/asm-generic/div64.h b/include/asm-generic/div64.h
[]
> @@ -25,6 +26,7 @@
>  # define do_div(n,base) ({					\
>  	uint32_t __base = (base);				\
>  	uint32_t __rem;						\
> +	BUG_ON(sizeof(base) > 4 && base >= (1UL<<32));		\

I think this would be better as a BUILD_BUG_ON


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