linux-kernel - Re: [announce] smatch 1.54

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Date:	Wed, 02 Jun 2010 12:20:46 -0700
From:	Roland Dreier <rdreier@...co.com>
To:	Dan Carpenter <error27@...il.com>
Cc:	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [announce] smatch 1.54

Hi Dan,

I'm trying out smatch on some kernel code now.  Neat stuff, but I'm
seeing some puzzling false positives relating to signedness.  Basically,
if I have code like:

	__be16 foo;
	__u16 bar;

	foo = cpu_to_be16(128);
	bar = cpu_to_be16(128);

then the first line warns about 32768 not fitting into foo, but while
the second line doesn't warn, even though __be16 is just a __bitwise__
__u16.  I don't understand the sparse / smatch internals so I'm not sure
why applying __bitwise__ apparently kills the unsigned modifier.  Maybe
it's an easy fix for you?  Otherwise I'll poke at it a little later.

Thanks,
  Roland
-- 
Roland Dreier <rolandd@...co.com> || For corporate legal information go to:
http://www.cisco.com/web/about/doing_business/legal/cri/index.html
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