Re: [PATCH ] cpufreq: ti-cpufreq: kfree opp_data when failure

[Zumeng Chen <zumeng.chen@windriver.com>]

On 09/28/2017 01:40 AM, Viresh Kumar wrote:
> On 27-09-17, 15:08, Zumeng Chen wrote:
>> From: Zumeng Chen <zumeng.chen@gmail.com>
>>
>> memory leakage was found by kmemleak. opp_data needs to be freed
>> when failure, including fail_put_node.
>>
>> unreferenced object 0xccdd4c40 (size 64):
>>    comm "swapper", pid 1, jiffies 4294938465 (age 888.520s)
>>    hex dump (first 32 bytes):
>>      00 7c 00 c1 98 69 d8 ce 00 24 03 ce 00 24 03 ce  .|...i...$...$..
>>      20 35 23 c1 00 00 00 00 00 00 00 00 00 00 00 00   5#.............
>>    backtrace:
>>      [<c028fb64>] kmem_cache_alloc_trace+0x2c4/0x3cc
>>      [<c076d5f0>] ti_cpufreq_probe+0x6c/0x334
>>      [<c068d6e4>] platform_drv_probe+0x60/0xc0
>>      [<c068b384>] driver_probe_device+0x218/0x2c4
>>      [<c068b5a4>] __device_attach_driver+0xa8/0xdc
>>      [<c0689340>] bus_for_each_drv+0x70/0xa4
>>      [<c068b020>] __device_attach+0xc0/0x124
>>      [<c068b634>] device_initial_probe+0x1c/0x20
>>      [<c068a3b8>] bus_probe_device+0x94/0x9c
>>      [<c0688300>] device_add+0x404/0x590
>>      [<c068d408>] platform_device_add+0x11c/0x230
>>      [<c068df40>] platform_device_register_full+0x10c/0x128
>>      [<c076d578>] ti_cpufreq_init+0x44/0x50
>>      [<c01017c4>] do_one_initcall+0x54/0x180
>>      [<c0e00fe0>] kernel_init_freeable+0x270/0x33c
>>      [<c093f2bc>] kernel_init+0x18/0x124
>>
>> Signed-off-by: Zumeng Chen <zumeng.chen@gmail.com>
>> ---
>>   drivers/cpufreq/ti-cpufreq.c | 5 ++++-
>>   1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/cpufreq/ti-cpufreq.c b/drivers/cpufreq/ti-cpufreq.c
>> index 4bf47de..ffcddcd 100644
>> --- a/drivers/cpufreq/ti-cpufreq.c
>> +++ b/drivers/cpufreq/ti-cpufreq.c
>> @@ -217,7 +217,8 @@ static int ti_cpufreq_init(void)
>>   	opp_data->cpu_dev = get_cpu_device(0);
>>   	if (!opp_data->cpu_dev) {
>>   		pr_err("%s: Failed to get device for CPU0\n", __func__);
>> -		return -ENODEV;
>> +		ret = ENODEV;
>> +		goto free_opp_data;
>>   	}
>>   
>>   	opp_data->opp_node = dev_pm_opp_of_get_opp_desc_node(opp_data->cpu_dev);
>> @@ -262,6 +263,8 @@ static int ti_cpufreq_init(void)
>>   
>>   fail_put_node:
>>   	of_node_put(opp_data->opp_node);
>> +free_opp_data:
>> +	kfree(opp_data);
>>   
>>   	return ret;
>>   }
> Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
>
> I also see that you are missing an of_node_put(np) in the driver. Maybe you
> want to fix that as well (in a separate patch) ?

Ha, thanks, I'm not sure if I follow your meanings.

opp_data->opp_node will be set after goto free_opp_data, so are we safe 
here?

         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;
         }

         opp_data->opp_node = 
dev_pm_opp_of_get_opp_desc_node(opp_data->cpu_dev);

Cheers,
Zumeng

>