[PATCH] extcon: palmas: Fail gracefully if invalid configuration

[PATCH] extcon: palmas: Fail gracefully if invalid configuration

[Roger Quadros]

extcon-palmas must be child of palmas and expects parent's
drvdata to be valid. Check for non NULL parent drvdata and
fail if it is NULL. Not doing so will result in a NULL
pointer dereference later in the probe() parent drvdata
is NULL (e.g. misplaced extcon-palmas node in device tree).

Signed-off-by: Roger Quadros <rogerq@ti.com>
---
 drivers/extcon/extcon-palmas.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/extcon/extcon-palmas.c b/drivers/extcon/extcon-palmas.c
index 634ba70..ec987ab 100644
--- a/drivers/extcon/extcon-palmas.c
+++ b/drivers/extcon/extcon-palmas.c
@@ -190,6 +190,11 @@ static int palmas_usb_probe(struct platform_device *pdev)
 	struct palmas_usb *palmas_usb;
 	int status;
 
+	if (!palmas) {
+		dev_err(&pdev->dev, "device has invalid parent\n");
+		return -EINVAL;
+	}
+
 	palmas_usb = devm_kzalloc(&pdev->dev, sizeof(*palmas_usb), GFP_KERNEL);
 	if (!palmas_usb)
 		return -ENOMEM;
-- 
2.7.4

Re: [PATCH] extcon: palmas: Fail gracefully if invalid configuration

[Chanwoo Choi]

Hi Roger,

Looks good to me.
But I have some comment.

How about changing the subject as following?

- old : Fail gracefully if invalid configuration
- new : Check the parent instance to prevent the NULL pointer error

On 2016년 12월 07일 21:12, Roger Quadros wrote:
> extcon-palmas must be child of palmas and expects parent's
> drvdata to be valid. Check for non NULL parent drvdata and
> fail if it is NULL. Not doing so will result in a NULL
> pointer dereference later in the probe() parent drvdata
> is NULL (e.g. misplaced extcon-palmas node in device tree).
> 
> Signed-off-by: Roger Quadros <rogerq@ti.com>
> ---
>  drivers/extcon/extcon-palmas.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/extcon/extcon-palmas.c b/drivers/extcon/extcon-palmas.c
> index 634ba70..ec987ab 100644
> --- a/drivers/extcon/extcon-palmas.c
> +++ b/drivers/extcon/extcon-palmas.c
> @@ -190,6 +190,11 @@ static int palmas_usb_probe(struct platform_device *pdev)
>  	struct palmas_usb *palmas_usb;
>  	int status;
>  
> +	if (!palmas) {
> +		dev_err(&pdev->dev, "device has invalid parent\n");

How about changing the error message as following?
because the extcon-palmas used the 'failed to ..' style for error message.
- "failed to get valid parent"

> +		return -EINVAL;
> +	}
> +
>  	palmas_usb = devm_kzalloc(&pdev->dev, sizeof(*palmas_usb), GFP_KERNEL);
>  	if (!palmas_usb)
>  		return -ENOMEM;
> 


Best Regards,
Chanwoo Choi

Re: [PATCH] extcon: palmas: Fail gracefully if invalid configuration

[Roger Quadros]

Hi Chanwoo,

On 07/12/16 14:46, Chanwoo Choi wrote:
> Hi Roger,
> 
> Looks good to me.
> But I have some comment.
> 
> How about changing the subject as following?
> 
> - old : Fail gracefully if invalid configuration
> - new : Check the parent instance to prevent the NULL pointer error

I'm OK with this.

> 
> On 2016년 12월 07일 21:12, Roger Quadros wrote:
>> extcon-palmas must be child of palmas and expects parent's
>> drvdata to be valid. Check for non NULL parent drvdata and
>> fail if it is NULL. Not doing so will result in a NULL
>> pointer dereference later in the probe() parent drvdata
>> is NULL (e.g. misplaced extcon-palmas node in device tree).
>>
>> Signed-off-by: Roger Quadros <rogerq@ti.com>
>> ---
>>  drivers/extcon/extcon-palmas.c | 5 +++++
>>  1 file changed, 5 insertions(+)
>>
>> diff --git a/drivers/extcon/extcon-palmas.c b/drivers/extcon/extcon-palmas.c
>> index 634ba70..ec987ab 100644
>> --- a/drivers/extcon/extcon-palmas.c
>> +++ b/drivers/extcon/extcon-palmas.c
>> @@ -190,6 +190,11 @@ static int palmas_usb_probe(struct platform_device *pdev)
>>  	struct palmas_usb *palmas_usb;
>>  	int status;
>>  
>> +	if (!palmas) {
>> +		dev_err(&pdev->dev, "device has invalid parent\n");
> 
> How about changing the error message as following?
> because the extcon-palmas used the 'failed to ..' style for error message.
> - "failed to get valid parent"

This is also fine.

I'll send a v2.

> 
>> +		return -EINVAL;
>> +	}
>> +
>>  	palmas_usb = devm_kzalloc(&pdev->dev, sizeof(*palmas_usb), GFP_KERNEL);
>>  	if (!palmas_usb)
>>  		return -ENOMEM;
>>
> 
> 

--
cheers,
-roger

[PATCH v2] extcon: palmas: Check the parent instance to prevent the NULL

[Roger Quadros]

extcon-palmas must be child of palmas and expects parent's
drvdata to be valid. Check for non NULL parent drvdata and
fail if it is NULL. Not doing so will result in a NULL
pointer dereference later in the probe() parent drvdata
is NULL (e.g. misplaced extcon-palmas node in device tree).

Signed-off-by: Roger Quadros <rogerq@ti.com>
---
Changelog:
v2:
- updated error message and commit message subject

 drivers/extcon/extcon-palmas.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/extcon/extcon-palmas.c b/drivers/extcon/extcon-palmas.c
index 634ba70..a128fd2 100644
--- a/drivers/extcon/extcon-palmas.c
+++ b/drivers/extcon/extcon-palmas.c
@@ -190,6 +190,11 @@ static int palmas_usb_probe(struct platform_device *pdev)
 	struct palmas_usb *palmas_usb;
 	int status;
 
+	if (!palmas) {
+		dev_err(&pdev->dev, "failed to get valid parent\n");
+		return -EINVAL;
+	}
+
 	palmas_usb = devm_kzalloc(&pdev->dev, sizeof(*palmas_usb), GFP_KERNEL);
 	if (!palmas_usb)
 		return -ENOMEM;
-- 
2.7.4