cpufreq: ti-cpufreq: Fix couple of minor issues in probe()

Message ID 20180326215244.26304-1-s-anna@ti.com
State New
Headers show
Series
  • cpufreq: ti-cpufreq: Fix couple of minor issues in probe()
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Commit Message

Suman Anna March 26, 2018, 9:52 p.m.
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>
Signed-off-by: Suman Anna <s-anna@ti.com>

---
 drivers/cpufreq/ti-cpufreq.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

-- 
2.16.2

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Comments

Zumeng Chen March 27, 2018, 2:10 a.m. | #1
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;

>   }



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Viresh Kumar April 2, 2018, 6:32 a.m. | #2
On 26-03-18, 16:52, 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


I don't agree to this reasoning for this particular patch. The code is just fine
and kmemleak is something that requires a fix.

> 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.


Maybe that could have been fixed in a separate patch, cc'ing stable kernels as
well.

> 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>

> 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;

>  }


I am fine with the diff though, as that makes sense. So maybe do this ?

- send separate patch for ENODEV thing
- and another patch to move to devres with a different reason than fixing false
  positive.

-- 
viresh
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Suman Anna April 2, 2018, 3:45 p.m. | #3
Hi Viresh,

On 04/02/2018 01:32 AM, Viresh Kumar wrote:
> On 26-03-18, 16:52, 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

> 

> I don't agree to this reasoning for this particular patch. The code is just fine

> and kmemleak is something that requires a fix.

> 

>> 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.

> 

> Maybe that could have been fixed in a separate patch, cc'ing stable kernels as

> well.

> 

>> 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>

>> 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;

>>  }

> 

> I am fine with the diff though, as that makes sense. So maybe do this ?

> 

> - send separate patch for ENODEV thing

> - and another patch to move to devres with a different reason than fixing false

>   positive


OK, thanks for your comments. Will split this patch and post the new
patches.

regards
Suman
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Patch

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;
 }