[PATCH] pinctrl-exynos5440: Use off-stack memory for pinctrl_gpio_range

[PATCH] pinctrl-exynos5440: Use off-stack memory for pinctrl_gpio_range

[Andrew Jeffery]

The range is registered into a linked list which can be referenced
throughout the lifetime of the driver. Ensure the range's memory is useful
for the same lifetime by adding it to the driver's private data structure.

The bug was introduced in the driver's initial commit, which was present in
v3.10.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Fixes: f0b9a7e521fa ("pinctrl: exynos5440: add pinctrl driver for Samsung EXYNOS5440 SoC")
Cc: stable@vger.kernel.org
---
This is my first contribution to the kernel, so hopefully I've followed all the
relevant documentation. If not, please let me know and point me in the right
direction!

I don't have the means to test the patch, but it compiles. Someone with
appropriate hardware should probably give it a spin.

 drivers/pinctrl/samsung/pinctrl-exynos5440.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/pinctrl/samsung/pinctrl-exynos5440.c b/drivers/pinctrl/samsung/pinctrl-exynos5440.c
index 00ab63abf1d9..d45028a75c0f 100644
--- a/drivers/pinctrl/samsung/pinctrl-exynos5440.c
+++ b/drivers/pinctrl/samsung/pinctrl-exynos5440.c
@@ -117,6 +117,7 @@ struct exynos5440_pinctrl_priv_data {
 	unsigned int			nr_groups;
 	const struct exynos5440_pmx_func	*pmx_functions;
 	unsigned int			nr_functions;
+	struct pinctrl_gpio_range	range;
 };
 
 /**
@@ -742,7 +743,6 @@ static int exynos5440_pinctrl_register(struct platform_device *pdev,
 	struct pinctrl_desc *ctrldesc;
 	struct pinctrl_dev *pctl_dev;
 	struct pinctrl_pin_desc *pindesc, *pdesc;
-	struct pinctrl_gpio_range grange;
 	char *pin_names;
 	int pin, ret;
 
@@ -794,12 +794,12 @@ static int exynos5440_pinctrl_register(struct platform_device *pdev,
 		return PTR_ERR(pctl_dev);
 	}
 
-	grange.name = "exynos5440-pctrl-gpio-range";
-	grange.id = 0;
-	grange.base = 0;
-	grange.npins = EXYNOS5440_MAX_PINS;
-	grange.gc = priv->gc;
-	pinctrl_add_gpio_range(pctl_dev, &grange);
+	priv->range.name = "exynos5440-pctrl-gpio-range";
+	priv->range.id = 0;
+	priv->range.base = 0;
+	priv->range.npins = EXYNOS5440_MAX_PINS;
+	priv->range.gc = priv->gc;
+	pinctrl_add_gpio_range(pctl_dev, &priv->range);
 	return 0;
 }
 
-- 
2.5.0

Re: [PATCH] pinctrl-exynos5440: Use off-stack memory for pinctrl_gpio_range

[Tomasz Figa]

Hi Andrew,

2016-04-19 13:13 GMT+09:00 Andrew Jeffery <andrew@aj.id.au>:
> The range is registered into a linked list which can be referenced
> throughout the lifetime of the driver. Ensure the range's memory is useful
> for the same lifetime by adding it to the driver's private data structure.
>
> The bug was introduced in the driver's initial commit, which was present in
> v3.10.
>
> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
> Fixes: f0b9a7e521fa ("pinctrl: exynos5440: add pinctrl driver for Samsung EXYNOS5440 SoC")
> Cc: stable@vger.kernel.org
> ---
> This is my first contribution to the kernel, so hopefully I've followed all the
> relevant documentation. If not, please let me know and point me in the right
> direction!
>
> I don't have the means to test the patch, but it compiles. Someone with
> appropriate hardware should probably give it a spin.
>

Thanks for the patch. Good catch, I wonder how this even worked. Just
one minor nitpick below.

Unfortunately I don't have any platform based on this SoC to test, so
I'll defer to Krzysztof or Sylwester to handle this.

Given the nitpick is fixed:

Acked-by: Tomasz Figa <tomasz.figa@gmail.com>

>  drivers/pinctrl/samsung/pinctrl-exynos5440.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/pinctrl/samsung/pinctrl-exynos5440.c b/drivers/pinctrl/samsung/pinctrl-exynos5440.c
> index 00ab63abf1d9..d45028a75c0f 100644
> --- a/drivers/pinctrl/samsung/pinctrl-exynos5440.c
> +++ b/drivers/pinctrl/samsung/pinctrl-exynos5440.c
> @@ -117,6 +117,7 @@ struct exynos5440_pinctrl_priv_data {
>         unsigned int                    nr_groups;
>         const struct exynos5440_pmx_func        *pmx_functions;
>         unsigned int                    nr_functions;
> +       struct pinctrl_gpio_range       range;

It would be nice to also describe this field in the kerneldoc comment
above the struct.

Best regards,
Tomasz

Re: [PATCH] pinctrl-exynos5440: Use off-stack memory for pinctrl_gpio_range

[Krzysztof Kozlowski]

On 04/19/2016 09:24 AM, Tomasz Figa wrote:
> Hi Andrew,
> 
> 2016-04-19 13:13 GMT+09:00 Andrew Jeffery <andrew@aj.id.au>:
>> The range is registered into a linked list which can be referenced
>> throughout the lifetime of the driver. Ensure the range's memory is useful
>> for the same lifetime by adding it to the driver's private data structure.
>>
>> The bug was introduced in the driver's initial commit, which was present in
>> v3.10.
>>
>> Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
>> Fixes: f0b9a7e521fa ("pinctrl: exynos5440: add pinctrl driver for Samsung EXYNOS5440 SoC")
>> Cc: stable@vger.kernel.org
>> ---
>> This is my first contribution to the kernel, so hopefully I've followed all the
>> relevant documentation. If not, please let me know and point me in the right
>> direction!
>>
>> I don't have the means to test the patch, but it compiles. Someone with
>> appropriate hardware should probably give it a spin.
>>
> 
> Thanks for the patch. Good catch, I wonder how this even worked. Just
> one minor nitpick below.
> 
> Unfortunately I don't have any platform based on this SoC to test, so
> I'll defer to Krzysztof or Sylwester to handle this.

We don't have this board neither, it is not so popular and apparently
not many people are using it because such bug remained unnoticed.

Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>

Best regards,
Krzysztof