[PATCH] platform/mellanox: Add a null pointer check in mlxbf_pmc_create_groups

[PATCH] platform/mellanox: Add a null pointer check in mlxbf_pmc_create_groups

[Kunwu Chan]

devm_kasprintf() returns a pointer to dynamically allocated memory
which can be NULL upon failure.

Fixes: 1a218d312e65 ("platform/mellanox: mlxbf-pmc: Add Mellanox BlueField PMC driver")
Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
---
 drivers/platform/mellanox/mlxbf-pmc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/platform/mellanox/mlxbf-pmc.c b/drivers/platform/mellanox/mlxbf-pmc.c
index 0b427fc24a96..59bbe5e13f6b 100644
--- a/drivers/platform/mellanox/mlxbf-pmc.c
+++ b/drivers/platform/mellanox/mlxbf-pmc.c
@@ -1882,6 +1882,8 @@ static int mlxbf_pmc_create_groups(struct device *dev, int blk_num)
 	pmc->block[blk_num].block_attr_grp.attrs = pmc->block[blk_num].block_attr;
 	pmc->block[blk_num].block_attr_grp.name = devm_kasprintf(
 		dev, GFP_KERNEL, pmc->block_name[blk_num]);
+	if (!pmc->block[blk_num].block_attr_grp.name)
+		return -ENOMEM;
 	pmc->groups[pmc->group_num] = &pmc->block[blk_num].block_attr_grp;
 	pmc->group_num++;
 
-- 
2.34.1

Re: [PATCH] platform/mellanox: Add a null pointer check in mlxbf_pmc_create_groups

[Hans de Goede]

Hi,

On 11/27/23 07:34, Kunwu Chan wrote:
> devm_kasprintf() returns a pointer to dynamically allocated memory
> which can be NULL upon failure.
> 
> Fixes: 1a218d312e65 ("platform/mellanox: mlxbf-pmc: Add Mellanox BlueField PMC driver")
> Signed-off-by: Kunwu Chan <chentao@kylinos.cn>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hdegoede@redhat.com>

Regards,

Hans


> ---
>  drivers/platform/mellanox/mlxbf-pmc.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/platform/mellanox/mlxbf-pmc.c b/drivers/platform/mellanox/mlxbf-pmc.c
> index 0b427fc24a96..59bbe5e13f6b 100644
> --- a/drivers/platform/mellanox/mlxbf-pmc.c
> +++ b/drivers/platform/mellanox/mlxbf-pmc.c
> @@ -1882,6 +1882,8 @@ static int mlxbf_pmc_create_groups(struct device *dev, int blk_num)
>  	pmc->block[blk_num].block_attr_grp.attrs = pmc->block[blk_num].block_attr;
>  	pmc->block[blk_num].block_attr_grp.name = devm_kasprintf(
>  		dev, GFP_KERNEL, pmc->block_name[blk_num]);
> +	if (!pmc->block[blk_num].block_attr_grp.name)
> +		return -ENOMEM;
>  	pmc->groups[pmc->group_num] = &pmc->block[blk_num].block_attr_grp;
>  	pmc->group_num++;
>  

Re: [PATCH] platform/mellanox: Add a null pointer check in mlxbf_pmc_create_groups

[Ilpo Järvinen]

On Mon, 27 Nov 2023, Kunwu Chan wrote:

> devm_kasprintf() returns a pointer to dynamically allocated memory
> which can be NULL upon failure.
> 
> Fixes: 1a218d312e65 ("platform/mellanox: mlxbf-pmc: Add Mellanox BlueField PMC driver")
> Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
> ---
>  drivers/platform/mellanox/mlxbf-pmc.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/platform/mellanox/mlxbf-pmc.c b/drivers/platform/mellanox/mlxbf-pmc.c
> index 0b427fc24a96..59bbe5e13f6b 100644
> --- a/drivers/platform/mellanox/mlxbf-pmc.c
> +++ b/drivers/platform/mellanox/mlxbf-pmc.c
> @@ -1882,6 +1882,8 @@ static int mlxbf_pmc_create_groups(struct device *dev, int blk_num)
>  	pmc->block[blk_num].block_attr_grp.attrs = pmc->block[blk_num].block_attr;
>  	pmc->block[blk_num].block_attr_grp.name = devm_kasprintf(
>  		dev, GFP_KERNEL, pmc->block_name[blk_num]);
> +	if (!pmc->block[blk_num].block_attr_grp.name)
> +		return -ENOMEM;
>  	pmc->groups[pmc->group_num] = &pmc->block[blk_num].block_attr_grp;
>  	pmc->group_num++;

I'm totally lost, why did you fix only one devm_kasprintf() location?
Don't all of them need this check?

-- 
 i.

Re: [PATCH] platform/mellanox: Add a null pointer check in mlxbf_pmc_create_groups

[Kunwu Chan]

Thanks for your reply.

Cause i don't know how to deal with in some scenario，such as in 
'mlxbf_pmc_init_perftype_counter', when 'attr->dev_attr.attr.name' is 
null, should return '-ENOMEM' or 'continue' the loop?

So I'm going to solve it one by one.

Thanks again,
Kunwu

On 2023/11/28 17:51, Ilpo Järvinen wrote:
> On Mon, 27 Nov 2023, Kunwu Chan wrote:
> 
>> devm_kasprintf() returns a pointer to dynamically allocated memory
>> which can be NULL upon failure.
>>
>> Fixes: 1a218d312e65 ("platform/mellanox: mlxbf-pmc: Add Mellanox BlueField PMC driver")
>> Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
>> ---
>>   drivers/platform/mellanox/mlxbf-pmc.c | 2 ++
>>   1 file changed, 2 insertions(+)
>>
>> diff --git a/drivers/platform/mellanox/mlxbf-pmc.c b/drivers/platform/mellanox/mlxbf-pmc.c
>> index 0b427fc24a96..59bbe5e13f6b 100644
>> --- a/drivers/platform/mellanox/mlxbf-pmc.c
>> +++ b/drivers/platform/mellanox/mlxbf-pmc.c
>> @@ -1882,6 +1882,8 @@ static int mlxbf_pmc_create_groups(struct device *dev, int blk_num)
>>   	pmc->block[blk_num].block_attr_grp.attrs = pmc->block[blk_num].block_attr;
>>   	pmc->block[blk_num].block_attr_grp.name = devm_kasprintf(
>>   		dev, GFP_KERNEL, pmc->block_name[blk_num]);
>> +	if (!pmc->block[blk_num].block_attr_grp.name)
>> +		return -ENOMEM;
>>   	pmc->groups[pmc->group_num] = &pmc->block[blk_num].block_attr_grp;
>>   	pmc->group_num++;
> 
> I'm totally lost, why did you fix only one devm_kasprintf() location?
> Don't all of them need this check?
> 

Re: [PATCH] platform/mellanox: Add a null pointer check in mlxbf_pmc_create_groups

[Ilpo Järvinen]

[-- Attachment #1: Type: text/plain, Size: 1959 bytes --]

Hi Vadim,

Could you please take a look at this and give advice to Kunwu so we can 
get all of them squashed in one go.

On Thu, 30 Nov 2023, Kunwu Chan wrote:

> Thanks for your reply.
> 
> Cause i don't know how to deal with in some scenario，such as in
> 'mlxbf_pmc_init_perftype_counter', when 'attr->dev_attr.attr.name' is null,
> should return '-ENOMEM' or 'continue' the loop?

I'd have thought returning -ENOMEM would be safe because it just ends up 
failing probe()? ...And it's not that likely to occur in the first place.

-- 
 i.

> 
> So I'm going to solve it one by one.
> 
> Thanks again,
> Kunwu
> 
> On 2023/11/28 17:51, Ilpo Järvinen wrote:
> > On Mon, 27 Nov 2023, Kunwu Chan wrote:
> > 
> > > devm_kasprintf() returns a pointer to dynamically allocated memory
> > > which can be NULL upon failure.
> > > 
> > > Fixes: 1a218d312e65 ("platform/mellanox: mlxbf-pmc: Add Mellanox BlueField
> > > PMC driver")
> > > Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
> > > ---
> > >   drivers/platform/mellanox/mlxbf-pmc.c | 2 ++
> > >   1 file changed, 2 insertions(+)
> > > 
> > > diff --git a/drivers/platform/mellanox/mlxbf-pmc.c
> > > b/drivers/platform/mellanox/mlxbf-pmc.c
> > > index 0b427fc24a96..59bbe5e13f6b 100644
> > > --- a/drivers/platform/mellanox/mlxbf-pmc.c
> > > +++ b/drivers/platform/mellanox/mlxbf-pmc.c
> > > @@ -1882,6 +1882,8 @@ static int mlxbf_pmc_create_groups(struct device
> > > *dev, int blk_num)
> > >   	pmc->block[blk_num].block_attr_grp.attrs =
> > > pmc->block[blk_num].block_attr;
> > >   	pmc->block[blk_num].block_attr_grp.name = devm_kasprintf(
> > >   		dev, GFP_KERNEL, pmc->block_name[blk_num]);
> > > +	if (!pmc->block[blk_num].block_attr_grp.name)
> > > +		return -ENOMEM;
> > >   	pmc->groups[pmc->group_num] = &pmc->block[blk_num].block_attr_grp;
> > >   	pmc->group_num++;
> > 
> > I'm totally lost, why did you fix only one devm_kasprintf() location?
> > Don't all of them need this check?
> > 
> 

RE: [PATCH] platform/mellanox: Add a null pointer check in mlxbf_pmc_create_groups

[Vadim Pasternak]

Hi Ilpo!

> -----Original Message-----
> From: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> Sent: Thursday, 30 November 2023 17:26
> To: Kunwu Chan <chentao@kylinos.cn>; Vadim Pasternak
> <vadimp@nvidia.com>
> Cc: Hans de Goede <hdegoede@redhat.com>; jiri@resnulli.us; Shravan
> Ramani <shravankr@nvidia.com>; kunwu.chan@hotmail.com; platform-
> driver-x86@vger.kernel.org; LKML <linux-kernel@vger.kernel.org>
> Subject: Re: [PATCH] platform/mellanox: Add a null pointer check in
> mlxbf_pmc_create_groups
> 
> Hi Vadim,
> 
> Could you please take a look at this and give advice to Kunwu so we can get all
> of them squashed in one go.

It seems there are six calls devm_kasprintf(), which requires checking pointer.

I guess, it is correct to return '-ENOMEM' for any failure.

I see there is another problem in mlxbf_pmc_probe() - it lacks error flow for:
	pmc->hwmon_dev = devm_hwmon_device_register_with_groups(
		dev, "bfperf", pmc, pmc->groups);
	
Need to add:
	if (IS_ERR(pmc->hwmon_dev))
		return PTR_ERR(pmc->hwmon_dev);

Sharvan, David,
Could you, please, have look?

> 
> On Thu, 30 Nov 2023, Kunwu Chan wrote:
> 
> > Thanks for your reply.
> >
> > Cause i don't know how to deal with in some scenario，such as in
> > 'mlxbf_pmc_init_perftype_counter', when 'attr->dev_attr.attr.name' is
> > null, should return '-ENOMEM' or 'continue' the loop?
> 
> I'd have thought returning -ENOMEM would be safe because it just ends up
> failing probe()? ...And it's not that likely to occur in the first place.
> 
> --
>  i.
> 
> >
> > So I'm going to solve it one by one.
> >
> > Thanks again,
> > Kunwu
> >
> > On 2023/11/28 17:51, Ilpo Järvinen wrote:
> > > On Mon, 27 Nov 2023, Kunwu Chan wrote:
> > >
> > > > devm_kasprintf() returns a pointer to dynamically allocated memory
> > > > which can be NULL upon failure.
> > > >
> > > > Fixes: 1a218d312e65 ("platform/mellanox: mlxbf-pmc: Add Mellanox
> > > > BlueField PMC driver")
> > > > Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
> > > > ---
> > > >   drivers/platform/mellanox/mlxbf-pmc.c | 2 ++
> > > >   1 file changed, 2 insertions(+)
> > > >
> > > > diff --git a/drivers/platform/mellanox/mlxbf-pmc.c
> > > > b/drivers/platform/mellanox/mlxbf-pmc.c
> > > > index 0b427fc24a96..59bbe5e13f6b 100644
> > > > --- a/drivers/platform/mellanox/mlxbf-pmc.c
> > > > +++ b/drivers/platform/mellanox/mlxbf-pmc.c
> > > > @@ -1882,6 +1882,8 @@ static int mlxbf_pmc_create_groups(struct
> > > > device *dev, int blk_num)
> > > >   	pmc->block[blk_num].block_attr_grp.attrs =
> > > > pmc->block[blk_num].block_attr;
> > > >   	pmc->block[blk_num].block_attr_grp.name = devm_kasprintf(
> > > >   		dev, GFP_KERNEL, pmc->block_name[blk_num]);
> > > > +	if (!pmc->block[blk_num].block_attr_grp.name)
> > > > +		return -ENOMEM;
> > > >   	pmc->groups[pmc->group_num] = &pmc-
> >block[blk_num].block_attr_grp;
> > > >   	pmc->group_num++;
> > >
> > > I'm totally lost, why did you fix only one devm_kasprintf() location?
> > > Don't all of them need this check?
> > >
> >

Re: [PATCH] platform/mellanox: Add a null pointer check in mlxbf_pmc_create_groups

[Kunwu Chan]

Hi Vadim,
Thanks for your reply.

I will follw your suggestions and add some ‘fixes’ label in v2 patch.

Thanks again,
Kunwu


On 2023/12/1 00:01, Vadim Pasternak wrote:
> Hi Ilpo!
> 
>> -----Original Message-----
>> From: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
>> Sent: Thursday, 30 November 2023 17:26
>> To: Kunwu Chan <chentao@kylinos.cn>; Vadim Pasternak
>> <vadimp@nvidia.com>
>> Cc: Hans de Goede <hdegoede@redhat.com>; jiri@resnulli.us; Shravan
>> Ramani <shravankr@nvidia.com>; kunwu.chan@hotmail.com; platform-
>> driver-x86@vger.kernel.org; LKML <linux-kernel@vger.kernel.org>
>> Subject: Re: [PATCH] platform/mellanox: Add a null pointer check in
>> mlxbf_pmc_create_groups
>>
>> Hi Vadim,
>>
>> Could you please take a look at this and give advice to Kunwu so we can get all
>> of them squashed in one go.
> 
> It seems there are six calls devm_kasprintf(), which requires checking pointer.
> 
> I guess, it is correct to return '-ENOMEM' for any failure.
> 
> I see there is another problem in mlxbf_pmc_probe() - it lacks error flow for:
> 	pmc->hwmon_dev = devm_hwmon_device_register_with_groups(
> 		dev, "bfperf", pmc, pmc->groups);
> 	
> Need to add:
> 	if (IS_ERR(pmc->hwmon_dev))
> 		return PTR_ERR(pmc->hwmon_dev);
> 
> Sharvan, David,
> Could you, please, have look?
> 
>>
>> On Thu, 30 Nov 2023, Kunwu Chan wrote:
>>
>>> Thanks for your reply.
>>>
>>> Cause i don't know how to deal with in some scenario，such as in
>>> 'mlxbf_pmc_init_perftype_counter', when 'attr->dev_attr.attr.name' is
>>> null, should return '-ENOMEM' or 'continue' the loop?
>>
>> I'd have thought returning -ENOMEM would be safe because it just ends up
>> failing probe()? ...And it's not that likely to occur in the first place.
>>
>> --
>>   i.
>>
>>>
>>> So I'm going to solve it one by one.
>>>
>>> Thanks again,
>>> Kunwu
>>>
>>> On 2023/11/28 17:51, Ilpo Järvinen wrote:
>>>> On Mon, 27 Nov 2023, Kunwu Chan wrote:
>>>>
>>>>> devm_kasprintf() returns a pointer to dynamically allocated memory
>>>>> which can be NULL upon failure.
>>>>>
>>>>> Fixes: 1a218d312e65 ("platform/mellanox: mlxbf-pmc: Add Mellanox
>>>>> BlueField PMC driver")
>>>>> Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
>>>>> ---
>>>>>    drivers/platform/mellanox/mlxbf-pmc.c | 2 ++
>>>>>    1 file changed, 2 insertions(+)
>>>>>
>>>>> diff --git a/drivers/platform/mellanox/mlxbf-pmc.c
>>>>> b/drivers/platform/mellanox/mlxbf-pmc.c
>>>>> index 0b427fc24a96..59bbe5e13f6b 100644
>>>>> --- a/drivers/platform/mellanox/mlxbf-pmc.c
>>>>> +++ b/drivers/platform/mellanox/mlxbf-pmc.c
>>>>> @@ -1882,6 +1882,8 @@ static int mlxbf_pmc_create_groups(struct
>>>>> device *dev, int blk_num)
>>>>>    	pmc->block[blk_num].block_attr_grp.attrs =
>>>>> pmc->block[blk_num].block_attr;
>>>>>    	pmc->block[blk_num].block_attr_grp.name = devm_kasprintf(
>>>>>    		dev, GFP_KERNEL, pmc->block_name[blk_num]);
>>>>> +	if (!pmc->block[blk_num].block_attr_grp.name)
>>>>> +		return -ENOMEM;
>>>>>    	pmc->groups[pmc->group_num] = &pmc-
>>> block[blk_num].block_attr_grp;
>>>>>    	pmc->group_num++;
>>>>
>>>> I'm totally lost, why did you fix only one devm_kasprintf() location?
>>>> Don't all of them need this check?
>>>>
>>>