[PATCH] iio: fix memory leak for iio_gts_build_avail_scale_table()

[PATCH] iio: fix memory leak for iio_gts_build_avail_scale_table()

[Zicheng Qu]

In iio_gts_build_avail_scale_table(), the memory allocated for
per_time_gains is freed using kfree(per_time_gains) before return 0.
However, the type per_time_gains is 'int **', and the memory allocated
for its inner elements is not being freed, leading to a memory leak.

Cc: stable@vger.kernel.org # v6.6+
Fixes: 38416c28e168 ("iio: light: Add gain-time-scale helpers")
Signed-off-by: Zicheng Qu <quzicheng@huawei.com>
---
 drivers/iio/industrialio-gts-helper.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/iio/industrialio-gts-helper.c b/drivers/iio/industrialio-gts-helper.c
index 59d7615c0f56..f2450b2e740d 100644
--- a/drivers/iio/industrialio-gts-helper.c
+++ b/drivers/iio/industrialio-gts-helper.c
@@ -307,6 +307,8 @@ static int iio_gts_build_avail_scale_table(struct iio_gts *gts)
 	if (ret)
 		goto err_free_out;
 
+	for (j = 0; j < gts->num_itime; j++)
+		kfree(per_time_gains[i]);
 	kfree(per_time_gains);
 	gts->per_time_avail_scale_tables = per_time_scales;
 
-- 
2.34.1

Re: [PATCH] iio: fix memory leak for iio_gts_build_avail_scale_table()

[Matti Vaittinen]

Hi Zicheng

On 31/10/2024 03:47, Zicheng Qu wrote:
> In iio_gts_build_avail_scale_table(), the memory allocated for
> per_time_gains is freed using kfree(per_time_gains) before return 0.
> However, the type per_time_gains is 'int **', and the memory allocated
> for its inner elements is not being freed, leading to a memory leak.
> 
> Cc: stable@vger.kernel.org # v6.6+
> Fixes: 38416c28e168 ("iio: light: Add gain-time-scale helpers")
> Signed-off-by: Zicheng Qu <quzicheng@huawei.com>
> ---
>   drivers/iio/industrialio-gts-helper.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/iio/industrialio-gts-helper.c b/drivers/iio/industrialio-gts-helper.c
> index 59d7615c0f56..f2450b2e740d 100644
> --- a/drivers/iio/industrialio-gts-helper.c
> +++ b/drivers/iio/industrialio-gts-helper.c
> @@ -307,6 +307,8 @@ static int iio_gts_build_avail_scale_table(struct iio_gts *gts)
>   	if (ret)
>   		goto err_free_out;
>   
> +	for (j = 0; j < gts->num_itime; j++)
> +		kfree(per_time_gains[i]);
>   	kfree(per_time_gains);
>   	gts->per_time_avail_scale_tables = per_time_scales;
>   

You're right, thanks!
This, however, was already fixed by:
https://lore.kernel.org/all/20241011095512.3667549-1-ruanjinjie@huawei.com/

Out of the curiosity (and no need to respond if you don't feel like) - 
are you using the gts helpers in some of your project(s)? I am glad 
seeing these fixes coming in and just wondered if all these bugs are 
found because these helpers are being used outside the ROHM drivers :)

Yours,
	-- Matti

Re: [PATCH] iio: fix memory leak for iio_gts_build_avail_scale_table()

[Zicheng Qu]

Hi Matti,

Thank you for your concern! I haven't used it in my projects yet. I came 
across this issue while using smatch for code analysis. After reviewing 
the code, I noticed a few minor issues. However, I did not realize that 
the patch for the memory leak has already been submitted couple of days 
ago. Apologies for not checking the patches thoroughly and submitting a 
duplicate.

Yours,

-- Zicheng

On 2024/10/31 15:32, Matti Vaittinen wrote:
> Hi Zicheng
>
> On 31/10/2024 03:47, Zicheng Qu wrote:
>> In iio_gts_build_avail_scale_table(), the memory allocated for
>> per_time_gains is freed using kfree(per_time_gains) before return 0.
>> However, the type per_time_gains is 'int **', and the memory allocated
>> for its inner elements is not being freed, leading to a memory leak.
>>
>> Cc: stable@vger.kernel.org # v6.6+
>> Fixes: 38416c28e168 ("iio: light: Add gain-time-scale helpers")
>> Signed-off-by: Zicheng Qu <quzicheng@huawei.com>
>> ---
>>   drivers/iio/industrialio-gts-helper.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/iio/industrialio-gts-helper.c 
>> b/drivers/iio/industrialio-gts-helper.c
>> index 59d7615c0f56..f2450b2e740d 100644
>> --- a/drivers/iio/industrialio-gts-helper.c
>> +++ b/drivers/iio/industrialio-gts-helper.c
>> @@ -307,6 +307,8 @@ static int iio_gts_build_avail_scale_table(struct 
>> iio_gts *gts)
>>       if (ret)
>>           goto err_free_out;
>>   +    for (j = 0; j < gts->num_itime; j++)
>> +        kfree(per_time_gains[i]);
>>       kfree(per_time_gains);
>>       gts->per_time_avail_scale_tables = per_time_scales;
>
> You're right, thanks!
> This, however, was already fixed by:
> https://lore.kernel.org/all/20241011095512.3667549-1-ruanjinjie@huawei.com/ 
>
>
> Out of the curiosity (and no need to respond if you don't feel like) - 
> are you using the gts helpers in some of your project(s)? I am glad 
> seeing these fixes coming in and just wondered if all these bugs are 
> found because these helpers are being used outside the ROHM drivers :)
>
> Yours,
>     -- Matti
>