mtk-pmic-keys being a child device of mt6397, it will always get probed
when mt6397_probe() is called.
This also happens when we have no device tree node matching
mediatek,mt6397-keys.
In that case, the mfd core warns us:
[ 0.352175] mtk-pmic-keys: Failed to locate of_node [id: -1]
Check return value from call to of_match_device()
in order to prevent a NULL pointer dereference.
In case of NULL print error message and return -ENODEV
Signed-off-by: Mattijs Korpershoek <[email protected]>
---
drivers/input/keyboard/mtk-pmic-keys.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/input/keyboard/mtk-pmic-keys.c b/drivers/input/keyboard/mtk-pmic-keys.c
index 62391d6c7da6..12c449eed026 100644
--- a/drivers/input/keyboard/mtk-pmic-keys.c
+++ b/drivers/input/keyboard/mtk-pmic-keys.c
@@ -247,6 +247,9 @@ static int mtk_pmic_keys_probe(struct platform_device *pdev)
const struct of_device_id *of_id =
of_match_device(of_mtk_pmic_keys_match_tbl, &pdev->dev);
+ if (!of_id)
+ return -ENODEV;
+
keys = devm_kzalloc(&pdev->dev, sizeof(*keys), GFP_KERNEL);
if (!keys)
return -ENOMEM;
--
2.27.0
Hi Mattijs,
On Wed, Apr 28, 2021 at 06:42:13PM +0200, Mattijs Korpershoek wrote:
> mtk-pmic-keys being a child device of mt6397, it will always get probed
> when mt6397_probe() is called.
>
> This also happens when we have no device tree node matching
> mediatek,mt6397-keys.
It sounds for me that creating a platform device instance in case where
we know need OF node, but do not have one, is wasteful. Can
mt6397-core.c and/or MFD core be adjusted to not do that.
>
> In that case, the mfd core warns us:
>
> [ 0.352175] mtk-pmic-keys: Failed to locate of_node [id: -1]
>
> Check return value from call to of_match_device()
> in order to prevent a NULL pointer dereference.
>
> In case of NULL print error message and return -ENODEV
>
> Signed-off-by: Mattijs Korpershoek <[email protected]>
> ---
> drivers/input/keyboard/mtk-pmic-keys.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/input/keyboard/mtk-pmic-keys.c b/drivers/input/keyboard/mtk-pmic-keys.c
> index 62391d6c7da6..12c449eed026 100644
> --- a/drivers/input/keyboard/mtk-pmic-keys.c
> +++ b/drivers/input/keyboard/mtk-pmic-keys.c
> @@ -247,6 +247,9 @@ static int mtk_pmic_keys_probe(struct platform_device *pdev)
> const struct of_device_id *of_id =
> of_match_device(of_mtk_pmic_keys_match_tbl, &pdev->dev);
>
> + if (!of_id)
> + return -ENODEV;
> +
So if we make MFD/6396 core smarter we would not be needing this. I
guess there is still a possibility of someone stuffing "mtk-pmic-keys"
into "driver_override" attribute of a random platform device but I
wonder if we really need to take care of such scenarios...
> keys = devm_kzalloc(&pdev->dev, sizeof(*keys), GFP_KERNEL);
> if (!keys)
> return -ENOMEM;
> --
> 2.27.0
>
Thanks.
--
Dmitry
Hi Dmitry,
Dmitry Torokhov <[email protected]> writes:
> Hi Mattijs,
>
> On Wed, Apr 28, 2021 at 06:42:13PM +0200, Mattijs Korpershoek wrote:
>> mtk-pmic-keys being a child device of mt6397, it will always get probed
>> when mt6397_probe() is called.
>>
>> This also happens when we have no device tree node matching
>> mediatek,mt6397-keys.
>
> It sounds for me that creating a platform device instance in case where
> we know need OF node, but do not have one, is wasteful. Can
> mt6397-core.c and/or MFD core be adjusted to not do that.
You are right. Maybe I can fix MFD core instead. I will look into it.
Thanks for your review.
>
>>
>> In that case, the mfd core warns us:
>>
>> [ 0.352175] mtk-pmic-keys: Failed to locate of_node [id: -1]
>>
>> Check return value from call to of_match_device()
>> in order to prevent a NULL pointer dereference.
>>
>> In case of NULL print error message and return -ENODEV
>>
>> Signed-off-by: Mattijs Korpershoek <[email protected]>
>> ---
>> drivers/input/keyboard/mtk-pmic-keys.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/input/keyboard/mtk-pmic-keys.c b/drivers/input/keyboard/mtk-pmic-keys.c
>> index 62391d6c7da6..12c449eed026 100644
>> --- a/drivers/input/keyboard/mtk-pmic-keys.c
>> +++ b/drivers/input/keyboard/mtk-pmic-keys.c
>> @@ -247,6 +247,9 @@ static int mtk_pmic_keys_probe(struct platform_device *pdev)
>> const struct of_device_id *of_id =
>> of_match_device(of_mtk_pmic_keys_match_tbl, &pdev->dev);
>>
>> + if (!of_id)
>> + return -ENODEV;
>> +
>
> So if we make MFD/6396 core smarter we would not be needing this. I
> guess there is still a possibility of someone stuffing "mtk-pmic-keys"
> into "driver_override" attribute of a random platform device but I
> wonder if we really need to take care of such scenarios...
>
>> keys = devm_kzalloc(&pdev->dev, sizeof(*keys), GFP_KERNEL);
>> if (!keys)
>> return -ENOMEM;
>> --
>> 2.27.0
>>
>
> Thanks.
>
> --
> Dmitry
Hi Dmitry,
Mattijs Korpershoek <[email protected]> writes:
> Hi Dmitry,
>
> Dmitry Torokhov <[email protected]> writes:
>
>> Hi Mattijs,
>>
>> On Wed, Apr 28, 2021 at 06:42:13PM +0200, Mattijs Korpershoek wrote:
>>> mtk-pmic-keys being a child device of mt6397, it will always get probed
>>> when mt6397_probe() is called.
>>>
>>> This also happens when we have no device tree node matching
>>> mediatek,mt6397-keys.
>>
>> It sounds for me that creating a platform device instance in case where
>> we know need OF node, but do not have one, is wasteful. Can
>> mt6397-core.c and/or MFD core be adjusted to not do that.
>
> You are right. Maybe I can fix MFD core instead. I will look into it.
>
> Thanks for your review.
>>
>>>
>>> In that case, the mfd core warns us:
>>>
>>> [ 0.352175] mtk-pmic-keys: Failed to locate of_node [id: -1]
>>>
>>> Check return value from call to of_match_device()
>>> in order to prevent a NULL pointer dereference.
>>>
>>> In case of NULL print error message and return -ENODEV
>>>
>>> Signed-off-by: Mattijs Korpershoek <[email protected]>
>>> ---
>>> drivers/input/keyboard/mtk-pmic-keys.c | 3 +++
>>> 1 file changed, 3 insertions(+)
>>>
>>> diff --git a/drivers/input/keyboard/mtk-pmic-keys.c b/drivers/input/keyboard/mtk-pmic-keys.c
>>> index 62391d6c7da6..12c449eed026 100644
>>> --- a/drivers/input/keyboard/mtk-pmic-keys.c
>>> +++ b/drivers/input/keyboard/mtk-pmic-keys.c
>>> @@ -247,6 +247,9 @@ static int mtk_pmic_keys_probe(struct platform_device *pdev)
>>> const struct of_device_id *of_id =
>>> of_match_device(of_mtk_pmic_keys_match_tbl, &pdev->dev);
>>>
>>> + if (!of_id)
>>> + return -ENODEV;
>>> +
>>
>> So if we make MFD/6396 core smarter we would not be needing this. I
>> guess there is still a possibility of someone stuffing "mtk-pmic-keys"
>> into "driver_override" attribute of a random platform device but I
>> wonder if we really need to take care of such scenarios...
It turns out it was possible to make 6397-core smarter.
I've submitted [1] to replace this patch.
Thanks again for your suggestion. Please let me know if I should add
your Suggested-by: in [1].
[1] https://patchwork.kernel.org/project/linux-mediatek/patch/[email protected]/ instead
>>
>>> keys = devm_kzalloc(&pdev->dev, sizeof(*keys), GFP_KERNEL);
>>> if (!keys)
>>> return -ENOMEM;
>>> --
>>> 2.27.0
>>>
>>
>> Thanks.
>>
>> --
>> Dmitry