linux-kernel - Re: div64: Rework 64-bit type safety checks in do

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Message-ID: <20071217050512.GY8181@ftp.linux.org.uk>
Date:	Mon, 17 Dec 2007 05:05:12 +0000
From:	Al Viro <viro@....linux.org.uk>
To:	Paul Mundt <lethal@...ux-sh.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...e.hu>
Subject: Re: div64: Rework 64-bit type safety checks in do_div().

On Mon, Dec 17, 2007 at 12:20:19PM +0900, Paul Mundt wrote:
> (Adding Ingo to CC regarding kernel/lockdep_proc.c..)
 
> That seems to be an accurate asessment, yes. If do_div(s64, ...) is buggy
> behaviour, then the current check is fine, and the callsites should be
> corrected. Though if there's code in-tree that relies on s64 do_div, that seems
> to be a more problematic issue.

It is a bug and the only existing callers that manage to work are those that
make sure that signed value is positive.  Still asking for trouble...
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