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Subject: Re: [PATCH] cpufreq: ti-cpufreq: Fix couple of minor issues in
 probe()
To:     Suman Anna <s-anna@ti.com>, Viresh Kumar <viresh.kumar@linaro.org>
References: <20180326215244.26304-1-s-anna@ti.com>
Cc:     "Rafael J. Wysocki" <rjw@rjwysocki.net>,
        Dave Gerlach <d-gerlach@ti.com>, Tero Kristo <t-kristo@ti.com>,
        linux-omap@vger.kernel.org, linux-kernel@vger.kernel.org
From:   Zumeng Chen <zumeng.chen@gmail.com>
Message-ID: <5bbd266a-ddc6-296a-dcea-58dc8da6062a@gmail.com>
Date:   Tue, 27 Mar 2018 10:10:51 +0800
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On 03/27/2018 05:52 AM, Suman Anna wrote:
> Commit 05829d9431df ("cpufreq: ti-cpufreq: kfree opp_data when
> failure") has fixed a memory leak in the failure path, however
> kmemleak still keeps reporting a leak even on successful probes.
> This is a false-positive and is mostly a result of the opp_data
> variable not being stored anywhere in the probe function. The
> patch also returned a positive value on the get_cpu_device()
> failure instead of a negative value.
>
> unreferenced object 0xecae4d80 (size 64):
>    comm "swapper/0", pid 1, jiffies 4294937673 (age 154.420s)
>    hex dump (first 32 bytes):
>      10 40 d9 ee 74 b7 db ee 00 24 ac ec 20 a3 ea c0  .@..t....$.. ...
>      00 26 ac ec 00 00 00 00 00 00 00 00 00 00 00 00  .&..............
>    backtrace:
>      [<ec080d62>] platform_drv_probe+0x50/0xac
>      [<cbde8566>] driver_probe_device+0x24c/0x330
>      [<a5818eb4>] bus_for_each_drv+0x54/0xb8
>      [<2c6f7021>] __device_attach+0xcc/0x13c
>      [<a04478a2>] bus_probe_device+0x88/0x90
>      [<b322c963>] device_add+0x38c/0x5b4
>      [<6f1af99b>] platform_device_add+0x100/0x220
>      [<cef42bca>] platform_device_register_full+0xf0/0x104
>      [<4d492439>] ti_cpufreq_init+0x44/0x6c
>      [<81222e89>] do_one_initcall+0x48/0x190
>      [<3bebf42a>] kernel_init_freeable+0x1f4/0x2b8
>      [<230ad7df>] kernel_init+0x8/0x110
>      [<43a165c3>] ret_from_fork+0x14/0x20
>      [<  (null)>]   (null)
>      [<87288797>] 0xffffffff
>
> Fix both issues by replacing the previous logic by using the devres
> managed API for allocating the opp_data variable, and simplifying
> the get_cpu_device() failure return path.
>
> Fixes: 05829d9431df ("cpufreq: ti-cpufreq: kfree opp_data when failure")
> Cc: Zumeng Chen <zumeng.chen@gmail.com>

Acked, I'm aware of the false-postive one, this is good to fix both one, 
thanks~

Cheers,
Zumeng
> Signed-off-by: Suman Anna <s-anna@ti.com>
> ---
>   drivers/cpufreq/ti-cpufreq.c | 7 ++-----
>   1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/cpufreq/ti-cpufreq.c b/drivers/cpufreq/ti-cpufreq.c
> index a099b7bf74cd..7d353a21935b 100644
> --- a/drivers/cpufreq/ti-cpufreq.c
> +++ b/drivers/cpufreq/ti-cpufreq.c
> @@ -217,7 +217,7 @@ static int ti_cpufreq_probe(struct platform_device *pdev)
>   	if (!match)
>   		return -ENODEV;
>   
> -	opp_data = kzalloc(sizeof(*opp_data), GFP_KERNEL);
> +	opp_data = devm_kzalloc(&pdev->dev, sizeof(*opp_data), GFP_KERNEL);
>   	if (!opp_data)
>   		return -ENOMEM;
>   
> @@ -226,8 +226,7 @@ static int ti_cpufreq_probe(struct platform_device *pdev)
>   	opp_data->cpu_dev = get_cpu_device(0);
>   	if (!opp_data->cpu_dev) {
>   		pr_err("%s: Failed to get device for CPU0\n", __func__);
> -		ret = ENODEV;
> -		goto free_opp_data;
> +		return -ENODEV;
>   	}
>   
>   	opp_data->opp_node = dev_pm_opp_of_get_opp_desc_node(opp_data->cpu_dev);
> @@ -285,8 +284,6 @@ static int ti_cpufreq_probe(struct platform_device *pdev)
>   
>   fail_put_node:
>   	of_node_put(opp_data->opp_node);
> -free_opp_data:
> -	kfree(opp_data);
>   
>   	return ret;
>   }