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From: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
To: Stephen Boyd <sboyd@kernel.org>
Cc: Andy Gross <agross@kernel.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Michael Turquette <mturquette@baylibre.com>,
	"open list:DRM DRIVER FOR MSM ADRENO GPU" 
	<linux-arm-msm@vger.kernel.org>,
	"open list:COMMON CLK FRAMEWORK" <linux-clk@vger.kernel.org>,
	"open list:DRM DRIVER FOR MSM ADRENO GPU" 
	<dri-devel@lists.freedesktop.org>,
	freedreno <freedreno@lists.freedesktop.org>,
	Rob Clark <robdclark@chromium.org>,
	Daniel Palmer <daniel@0x0f.com>
Subject: Re: [PATCH] clk: fixed: fix double free in resource managed fixed-factor clock
Date: Thu, 8 Apr 2021 01:57:01 +0300
Message-ID: <CAA8EJppsM1sP=OTiMY8jsLLgU=+p3qgZDD7M+M5naJhfFEF_Zg@mail.gmail.com> (raw)
In-Reply-To: <161783530964.3790633.16412468884239960912@swboyd.mtv.corp.google.com>

On Thu, 8 Apr 2021 at 01:41, Stephen Boyd <sboyd@kernel.org> wrote:
>
> Quoting Dmitry Baryshkov (2021-04-06 16:06:06)
> > devm_clk_hw_register_fixed_factor_release(), the release function for
> > the devm_clk_hw_register_fixed_factor(), calls
> > clk_hw_unregister_fixed_factor(), which will kfree() the clock. However
> > after that the devres functions will also kfree the allocated data,
> > resulting in double free/memory corruption. Just call
> > clk_hw_unregister() instead, leaving kfree() to devres code.
> >
> > Reported-by: Rob Clark <robdclark@chromium.org>
> > Cc: Daniel Palmer <daniel@0x0f.com>
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > ---
> >
> > Stephen, this fix affects the DSI PHY rework. Do we have a chance of
> > getting it into 5.12, otherwise there will be a cross-dependency between
> > msm-next and clk-next.
>
> Think I can get this into the last fixes PR. One question though, I
> think this follows the pattern that things like clk-divider.c use for
> devm. Are those also broken?

It looks so. See e.g. the devres_release() function. It calls
(*release) callback, then it will kfree the resource.
Also see Documentation/driver-api/driver-model/devres.rst, which does
not kfree() in release functions.

Do you wish for me to send all the fixes?



-- 
With best wishes
Dmitry

  reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-06 23:06 Dmitry Baryshkov
2021-04-07  9:00 ` Dmitry Baryshkov
2021-04-07 11:38 ` Daniel Palmer
2021-04-07 22:41 ` Stephen Boyd
2021-04-07 22:57   ` Dmitry Baryshkov [this message]
     [not found]     ` <161783803315.3790633.10829887417379757624@swboyd.mtv.corp.google.com>
2021-04-08  0:52       ` Dmitry Baryshkov
2021-04-08  7:32         ` Stephen Boyd
2021-04-07 23:01 ` Stephen Boyd

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