linux-kernel - Re: [PATCH v2] cpufreq: qcom-kryo: Fix section mismatch warning

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Date:   Wed, 19 Sep 2018 14:45:15 -0700
From:   Nick Desaulniers <ndesaulniers@...gle.com>
To:     Nathan Chancellor <natechancellor@...il.com>
Cc:     ilia.lin@...il.com, rjw@...ysocki.net, viresh.kumar@...aro.org,
        linux-pm@...r.kernel.org, LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2] cpufreq: qcom-kryo: Fix section mismatch warning

On Wed, Sep 19, 2018 at 11:22 AM Nathan Chancellor
<natechancellor@...il.com> wrote:
>
> WARNING: vmlinux.o(.text+0x8aa424): Section mismatch in reference from
> the function qcom_cpufreq_kryo_probe() to the function
> .init.text:qcom_cpufreq_kryo_get_msm_id()
> The function qcom_cpufreq_kryo_probe() references
> the function __init qcom_cpufreq_kryo_get_msm_id().
> This is often because qcom_cpufreq_kryo_probe lacks a __init
> annotation or the annotation of qcom_cpufreq_kryo_get_msm_id is wrong.
>
> Add the '__init' annotation to qcom_cpufreq_kryo_probe so that there is
> no more mismatch warning.

I wonder why this driver has an exit function marked __init rather
than __exit? Does that mean it gets cleaned up after kernel init, and
so on unloading of the driver, the kernel jumps to unmapped memory?

Does this patch now produce a warning for `qcom_cpufreq_kryo_driver`
referencing `qcom_cpufreq_kryo_probe`?

>
> Fixes: 46e2856b8e18 ("cpufreq: Add Kryo CPU scaling driver")
> Reported-by: Nick Desaulniers <ndesaulniers@...gle.com>
> Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
> ---
>
> v1 -> v2:
>
> Add '__init' to qcom_cpufreq_kryo_probe instead of removing it from
> qcom_cpufreq_kryo_get_msm_id.
>
>  drivers/cpufreq/qcom-cpufreq-kryo.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/qcom-cpufreq-kryo.c b/drivers/cpufreq/qcom-cpufreq-kryo.c
> index a1830fa25fc5..e001ef8ea7de 100644
> --- a/drivers/cpufreq/qcom-cpufreq-kryo.c
> +++ b/drivers/cpufreq/qcom-cpufreq-kryo.c
> @@ -73,7 +73,7 @@ static enum _msm8996_version __init qcom_cpufreq_kryo_get_msm_id(void)
>         return version;
>  }
>
> -static int qcom_cpufreq_kryo_probe(struct platform_device *pdev)
> +static int __init qcom_cpufreq_kryo_probe(struct platform_device *pdev)
>  {
>         struct opp_table *opp_tables[NR_CPUS] = {0};
>         enum _msm8996_version msm8996_version;
> --
> 2.19.0
>


--
Thanks,
~Nick Desaulniers