linux-kernel - Re: [Patch] cpufreq: tegra194: fix warning due to missing opp

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Message-ID: <20230829055930.csddryecm72ehz3o@vireshk-i7>
Date:   Tue, 29 Aug 2023 11:29:30 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Sumit Gupta <sumitg@...dia.com>
Cc:     rafael@...nel.org, treding@...dia.com, jonathanh@...dia.com,
        linux-pm@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org, bbasu@...dia.com
Subject: Re: [Patch] cpufreq: tegra194: fix warning due to missing opp_put

On 28-08-23, 17:39, Sumit Gupta wrote:
> Fix the warning due to missing dev_pm_opp_put() call and hence
> wrong refcount value. This causes below warning message when
> trying to remove the module.
> 
>  Call trace:
>   dev_pm_opp_put_opp_table+0x154/0x15c
>   dev_pm_opp_remove_table+0x34/0xa0
>   _dev_pm_opp_cpumask_remove_table+0x7c/0xbc
>   dev_pm_opp_of_cpumask_remove_table+0x10/0x18
>   tegra194_cpufreq_exit+0x24/0x34 [tegra194_cpufreq]
>   cpufreq_remove_dev+0xa8/0xf8
>   subsys_interface_unregister+0x90/0xe8
>   cpufreq_unregister_driver+0x54/0x9c
>   tegra194_cpufreq_remove+0x18/0x2c [tegra194_cpufreq]
>   platform_remove+0x24/0x74
>   device_remove+0x48/0x78
>   device_release_driver_internal+0xc8/0x160
>   driver_detach+0x4c/0x90
>   bus_remove_driver+0x68/0xb8
>   driver_unregister+0x2c/0x58
>   platform_driver_unregister+0x10/0x18
>   tegra194_ccplex_driver_exit+0x14/0x1e0 [tegra194_cpufreq]
>   __arm64_sys_delete_module+0x184/0x270
> 
> Fixes: f41e1442ac5b ("cpufreq: tegra194: add OPP support and set bandwidth")
> Signed-off-by: Sumit Gupta <sumitg@...dia.com>
> ---
>  drivers/cpufreq/tegra194-cpufreq.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/cpufreq/tegra194-cpufreq.c b/drivers/cpufreq/tegra194-cpufreq.c
> index 88ef5e57ccd0..f63f7a6c2034 100644
> --- a/drivers/cpufreq/tegra194-cpufreq.c
> +++ b/drivers/cpufreq/tegra194-cpufreq.c
> @@ -454,6 +454,8 @@ static int tegra_cpufreq_init_cpufreq_table(struct cpufreq_policy *policy,

You need to put the OPP here, even if this fails.

>  		if (ret < 0)
>  			return ret;
>  
> +		dev_pm_opp_put(opp);
> +
>  		freq_table[j].driver_data = pos->driver_data;
>  		freq_table[j].frequency = pos->frequency;
>  		j++;
> -- 
> 2.17.1

-- 
viresh