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Date: Fri, 5 Jan 2018 16:40:04 +0800
From: Leo Yan <leo.yan@linaro.org>
To: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Wei Yongjun <weiyongjun1@huawei.com>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@codeaurora.org>,
	Kaihua Zhong <zhongkaihua@huawei.com>,
	Ruyi Wang <wangruyi@huawei.com>, Kai Zhao <zhaokai1@hisilicon.com>,
	Tao Wang <kevin.wangtao@hisilicon.com>,
	linux-clk <linux-clk@vger.kernel.org>
Subject: Re: [PATCH -next] clk: =?utf-8?Q?hisilicon?=
 =?utf-8?B?OiBoaTM2NjDvvJpGaQ==?= =?utf-8?Q?x?= potential NULL dereference in
 hi3660_stub_clk_probe()
Message-ID: <20180105084004.GC26855@leoy-linaro>
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 <CAK7LNAQXTg=A6udMPs4dptbaLz1U5+D4JBJaW0W8d_EgH_R1_A@mail.gmail.com>
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On Fri, Jan 05, 2018 at 12:59:38PM +0900, Masahiro Yamada wrote:
> 2018-01-04 15:36 GMT+09:00 Wei Yongjun <weiyongjun1@huawei.com>:
> > platform_get_resource() may return NULL, add proper check to
> > avoid potential NULL dereferencing.
> >
> > This is detected by Coccinelle semantic patch.
> >
> > @@
> > expression pdev, res, n, t, e, e1, e2;
> > @@
> >
> > res = platform_get_resource(pdev, t, n);
> > + if (!res)
> > +   return -EINVAL;
> > ... when != res == NULL
> > e = devm_ioremap(e1, res->start, e2);
> >
> > Fixes: 4f16f7ff3bc0 ("clk: hisilicon: Add support for Hi3660 stub clocks")
> > Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
> > ---
> >  drivers/clk/hisilicon/clk-hi3660-stub.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/drivers/clk/hisilicon/clk-hi3660-stub.c b/drivers/clk/hisilicon/clk-hi3660-stub.c
> > index 9b6c72b..e8b2c43 100644
> > --- a/drivers/clk/hisilicon/clk-hi3660-stub.c
> > +++ b/drivers/clk/hisilicon/clk-hi3660-stub.c
> > @@ -149,6 +149,8 @@ static int hi3660_stub_clk_probe(struct platform_device *pdev)
> >                 return PTR_ERR(stub_clk_chan.mbox);
> >
> >         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +       if (!res)
> > +               return -EINVAL;
> >         freq_reg = devm_ioremap(dev, res->start, resource_size(res));
> >         if (!freq_reg)
> >                 return -ENOMEM;
> 
> 
> Probably, it is better to use devm_ioremap_resource().
> This checks NULL input.

Thanks for suggestion, Masahiro. This is good suggestion.

Yongjun, could you spin new patch by using devm_ioremap_resource()
to replace devm_ioremap()?

Thanks,
Leo Yan