linux-kernel - Re: [PATCH] Coccinelle : Script to detect cast after memory allocation

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Message-ID: <alpine.DEB.2.02.1406142136480.2018@localhost6.localdomain6>
Date:	Sat, 14 Jun 2014 21:37:23 +0200 (CEST)
From:	Julia Lawall <julia.lawall@...6.fr>
To:	Himangi Saraogi <himangi774@...il.com>
cc:	Joe Perches <joe@...ches.com>, Julia Lawall <Julia.Lawall@...6.fr>,
	Gilles Muller <Gilles.Muller@...6.fr>,
	Nicolas Palix <nicolas.palix@...g.fr>,
	Michal Marek <mmarek@...e.cz>, cocci@...teme.lip6.fr,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Coccinelle : Script to detect cast after memory
 allocation

On Sun, 15 Jun 2014, Himangi Saraogi wrote:

> Hi,
> 
> I have run the generic rule but it does not detect the cases of
> cast where the k[mzc]alloc or the kmem functions are used. I have used
> flags like recursive-includes, as suggested by Julia, but not any of the
> cases covered by the original script are detected.

Are other things detected?  You could always expand the rule to be more 
comprehensive.

julia


> Thanks
> Himangi
> 
> 
> On 14 June 2014 22:31, Joe Perches <joe@...ches.com> wrote:
>       On Sat, 2014-06-14 at 18:11 +0200, Julia Lawall wrote:
>       > On Sat, 14 Jun 2014, Joe Perches wrote:
> []
> > > Perhaps make this more generic for any void *?
> > >
> > > Something like:
> > >
> > > @@
> > > void *t;
> > > type other;
> > > @@
> > >
> > > -       (other *)t
> > > +       t
> []
> > Perhaps it would be reasonable to add this among the specific
> functions.
> > That is, t could be part of the disjunctions.
> 
> You do have to make sure that the
> "casted to" type is not dereferenced.
> 
> ie: don't transform
> 
> void func(void *foo)
> {
>         unsigned long bar = *(unsigned long *)foo;
> }
> 
> Also there may be some __user cast types and
> such that may be necessary to exclude too.
> 
> 
> 
> 
> 
>