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Date: Tue, 27 Dec 2011 09:36:04 +0100 (CET)
From: Julia Lawall <julia.lawall@lip6.fr>
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To: Artem Bityutskiy <dedekind1@gmail.com>
cc: David Woodhouse <dwmw2@infradead.org>, kernel-janitors@vger.kernel.org,
        linux-mtd@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] drivers/mtd/maps/lantiq-flash.c: drop iounmap for
 devm_ allocated data
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On Tue, 27 Dec 2011, Artem Bityutskiy wrote:

> On Mon, 2011-12-26 at 18:38 +0100, Julia Lawall wrote:
>> From: Julia Lawall <julia@diku.dk>
>>
>> Data allocated with devm_ioremap or devm_ioremap_nocache should not be
>> freed using iounmap, because doing so causes a dangling pointer, and a
>> subsequent double free.
>>
>> The semantic match that finds this problem is as follows:
>> (http://coccinelle.lip6.fr/)
>>
>> // <smpl>
>> @r@
>> expression x;
>> @@
>> (
>>  x = devm_ioremap(...)
>> |
>>  x = devm_ioremap_nocache(...)
>> )
>>
>> @@
>> expression r.x;
>> @@
>> * iounmap(x)
>> // </smpl>
>
> Thanks Julia,
>
> surely this semantic patch script is worth adding to scripts/coccinelle?
> Are you going to take care of this?

OK, I will do that.

julia