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Subject: Re: [PATCH 07/16] clk: qcom: clk-krait: add hw_parent check for div2_round_rate
From:   Stephen Boyd <sboyd@kernel.org>
To:     Andy Gross <agross@kernel.org>,
        Ansuel Smith <ansuelsmth@gmail.com>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Michael Turquette <mturquette@baylibre.com>,
        Peter De Schrijver <pdeschrijver@nvidia.com>,
        Prashant Gaikwad <pgaikwad@nvidia.com>,
        Rob Herring <robh+dt@kernel.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org,
        linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-tegra@vger.kernel.org
Date:   Tue, 15 Mar 2022 15:43:36 -0700
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Message-Id: <20220315224338.BB736C340E8@smtp.kernel.org>
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Quoting Ansuel Smith (2022-03-13 12:04:10)
> Check if hw_parent is present before calculating the round_rate to
> prevent kernel panic.
>=20
> Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
> ---
>  drivers/clk/qcom/clk-krait.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
>=20
> diff --git a/drivers/clk/qcom/clk-krait.c b/drivers/clk/qcom/clk-krait.c
> index e447fcc3806d..d8af281eba0e 100644
> --- a/drivers/clk/qcom/clk-krait.c
> +++ b/drivers/clk/qcom/clk-krait.c
> @@ -80,7 +80,12 @@ EXPORT_SYMBOL_GPL(krait_mux_clk_ops);
>  static long krait_div2_round_rate(struct clk_hw *hw, unsigned long rate,
>                                   unsigned long *parent_rate)
>  {
> -       *parent_rate =3D clk_hw_round_rate(clk_hw_get_parent(hw), rate * =
2);
> +       struct clk_hw *hw_parent =3D clk_hw_get_parent(hw);
> +
> +       if (!hw_parent)
> +               return -1;

Use -EINVAL or some proper error code, not just -1

> +
> +       *parent_rate =3D clk_hw_round_rate(hw_parent, rate * 2);
>         return DIV_ROUND_UP(*parent_rate, 2);
>  }
> =20
> --=20
> 2.34.1
>