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Message-id: <1403870594.3872.0.camel@AMDC1943>
Subject: Re: [PATCH] clk: s2mps11: Fix double free corruption during driver
 unbind
From: Krzysztof Kozlowski <k.kozlowski@samsung.com>
To: Yadwinder Singh Brar <yadi.brar01@gmail.com>
Cc: Mike Turquette <mturquette@linaro.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Kyungmin Park <kyungmin.park@samsung.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        Tomasz Figa <t.figa@samsung.com>,
        Yadwinder Singh Brar <yadi.brar@samsung.com>,
        Tushar Behera <tushar.behera@linaro.org>
Date: Fri, 27 Jun 2014 14:03:14 +0200
In-reply-to: <CAKew6eWEnQkfWJfhNXnHGbDc5j8nmGBsKb48DvdS-jud-sKLBA@mail.gmail.com>
References: <1403865264-29062-1-git-send-email-k.kozlowski@samsung.com>
 <CAKew6eWEnQkfWJfhNXnHGbDc5j8nmGBsKb48DvdS-jud-sKLBA@mail.gmail.com>
Sender: linux-kernel-owner@vger.kernel.org

On pią, 2014-06-27 at 17:19 +0530, Yadwinder Singh Brar wrote:
> Hi Krzystof,
> 
> On Fri, Jun 27, 2014 at 4:04 PM, Krzysztof Kozlowski
> <k.kozlowski@samsung.com> wrote:
> > After unbinding the driver memory was corrupted by double free of
> > clk_lookup structure. This lead to OOPS when re-binding the driver
> > again.
> >
> > The driver allocated memory for 'clk_lookup' with devm_kzalloc. During
> > driver removal this memory was freed twice: once by clkdev_drop() and
> > second by devm code.
> >
> 
> Ideally memory should be allocated and deallocated in same place
> either driver or framework, so in this case if framework(clkdev_drop)
> deallocates memory, framework itself should also allocate it.
> So IMO this bug should be fixed using clkdev_alloc() instead of kzalloc().
> 

You're right, I'll send fixed version. Thanks for idea.

Best regards,
Krzysztof

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