2023-11-30 09:46:07

by Yu Sun

[permalink] [raw]
Subject: [PATCH] platform/mellanox: mlxreg-lc: Check before variable dereferenced

there is a warning saying variable dereferenced before
check 'data->notifier' in line 828.
add "for(data->notifier)" before variable deferenced.

Signed-off-by: Yu Sun <[email protected]>
Reviewed-by: Dongliang Mu <[email protected]>
Reviewed-by: Dan Carpenter <[email protected]>
---
drivers/platform/mellanox/mlxreg-lc.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/mellanox/mlxreg-lc.c b/drivers/platform/mellanox/mlxreg-lc.c
index 43d119e3a473..e92add40750b 100644
--- a/drivers/platform/mellanox/mlxreg-lc.c
+++ b/drivers/platform/mellanox/mlxreg-lc.c
@@ -824,9 +824,12 @@ static int mlxreg_lc_probe(struct platform_device *pdev)
return -ENOMEM;

mutex_init(&mlxreg_lc->lock);
- /* Set event notification callback. */
- data->notifier->user_handler = mlxreg_lc_event_handler;
- data->notifier->handle = mlxreg_lc;
+
+ if (data->notifier) {
+ /* Set event notification callback. */
+ data->notifier->user_handler = mlxreg_lc_event_handler;
+ data->notifier->handle = mlxreg_lc;
+ }

data->hpdev.adapter = i2c_get_adapter(data->hpdev.nr);
if (!data->hpdev.adapter) {
--
2.42.0


2023-11-30 11:47:45

by Dan Carpenter

[permalink] [raw]
Subject: Re: [PATCH] platform/mellanox: mlxreg-lc: Check before variable dereferenced

On Thu, Nov 30, 2023 at 05:44:07PM +0800, Yu Sun wrote:
> there is a warning saying variable dereferenced before
> check 'data->notifier' in line 828.
> add "for(data->notifier)" before variable deferenced.
^^^
Should have been "if (data->notifier)".

>
> Signed-off-by: Yu Sun <[email protected]>
> Reviewed-by: Dongliang Mu <[email protected]>
> Reviewed-by: Dan Carpenter <[email protected]>

I didn't really explicitly give a Reviewed-by tag for this patch.
https://groups.google.com/g/hust-os-kernel-patches/c/c5hUaYIDcII/m/h4aFS7PkCQAJ
I also said that I thought it looked correct but that it needed a Fixes:
tag however the Fixes tag I suggested was wrong.

Looking at it now, the correct Fixes tag would be:
Fixes: 1c8ee06b637f ("platform/mellanox: Remove unnecessary code")

That commit says that the NULL check is not required. So now I'm
confused. On the one hand, the impulse is to trust the maintainer, but
on the other hand my review suggested that the NULL check might be
required.

regards,
dan carpenter


2023-11-30 16:24:45

by Vadim Pasternak

[permalink] [raw]
Subject: RE: [PATCH] platform/mellanox: mlxreg-lc: Check before variable dereferenced

Hi Dan,

> -----Original Message-----
> From: Dan Carpenter <[email protected]>
> Sent: Thursday, 30 November 2023 13:47
> To: Yu Sun <[email protected]>
> Cc: Hans de Goede <[email protected]>; Ilpo Järvinen
> <[email protected]>; Mark Gross <[email protected]>; Vadim
> Pasternak <[email protected]>; hust-os-kernel-
> [email protected]; Dongliang Mu <[email protected]>; Dan
> Carpenter <[email protected]>; [email protected]; linux-
> [email protected]
> Subject: Re: [PATCH] platform/mellanox: mlxreg-lc: Check before variable
> dereferenced
>
> On Thu, Nov 30, 2023 at 05:44:07PM +0800, Yu Sun wrote:
> > there is a warning saying variable dereferenced before check
> > 'data->notifier' in line 828.
> > add "for(data->notifier)" before variable deferenced.
> ^^^
> Should have been "if (data->notifier)".
>
> >
> > Signed-off-by: Yu Sun <[email protected]>
> > Reviewed-by: Dongliang Mu <[email protected]>
> > Reviewed-by: Dan Carpenter <[email protected]>
>
> I didn't really explicitly give a Reviewed-by tag for this patch.
> https://groups.google.com/g/hust-os-kernel-
> patches/c/c5hUaYIDcII/m/h4aFS7PkCQAJ
> I also said that I thought it looked correct but that it needed a Fixes:
> tag however the Fixes tag I suggested was wrong.
>
> Looking at it now, the correct Fixes tag would be:
> Fixes: 1c8ee06b637f ("platform/mellanox: Remove unnecessary code")
>
> That commit says that the NULL check is not required. So now I'm confused.
> On the one hand, the impulse is to trust the maintainer, but on the other hand
> my review suggested that the NULL check might be required.

Yes, it indeed required.
My mistake.

Thank you for your comments.

>
> regards,
> dan carpenter
>

2023-12-02 11:40:07

by Hans de Goede

[permalink] [raw]
Subject: Re: [PATCH] platform/mellanox: mlxreg-lc: Check before variable dereferenced

Hi,

On 11/30/23 17:24, Vadim Pasternak wrote:
> Hi Dan,
>
>> -----Original Message-----
>> From: Dan Carpenter <[email protected]>
>> Sent: Thursday, 30 November 2023 13:47
>> To: Yu Sun <[email protected]>
>> Cc: Hans de Goede <[email protected]>; Ilpo Järvinen
>> <[email protected]>; Mark Gross <[email protected]>; Vadim
>> Pasternak <[email protected]>; hust-os-kernel-
>> [email protected]; Dongliang Mu <[email protected]>; Dan
>> Carpenter <[email protected]>; [email protected]; linux-
>> [email protected]
>> Subject: Re: [PATCH] platform/mellanox: mlxreg-lc: Check before variable
>> dereferenced
>>
>> On Thu, Nov 30, 2023 at 05:44:07PM +0800, Yu Sun wrote:
>>> there is a warning saying variable dereferenced before check
>>> 'data->notifier' in line 828.
>>> add "for(data->notifier)" before variable deferenced.
>> ^^^
>> Should have been "if (data->notifier)".
>>
>>>
>>> Signed-off-by: Yu Sun <[email protected]>
>>> Reviewed-by: Dongliang Mu <[email protected]>
>>> Reviewed-by: Dan Carpenter <[email protected]>
>>
>> I didn't really explicitly give a Reviewed-by tag for this patch.
>> https://groups.google.com/g/hust-os-kernel-
>> patches/c/c5hUaYIDcII/m/h4aFS7PkCQAJ
>> I also said that I thought it looked correct but that it needed a Fixes:
>> tag however the Fixes tag I suggested was wrong.
>>
>> Looking at it now, the correct Fixes tag would be:
>> Fixes: 1c8ee06b637f ("platform/mellanox: Remove unnecessary code")
>>
>> That commit says that the NULL check is not required. So now I'm confused.
>> On the one hand, the impulse is to trust the maintainer, but on the other hand
>> my review suggested that the NULL check might be required.
>
> Yes, it indeed required.
> My mistake.

Ok, so we are going to need a v2 of this addressing Dan's remarks
about the commit message.

Yu Sun, can you please submit a new version addressing
Dan's comments on the commit message ?

Regards,

Hans