[PATCH v5 1/3] mtd: rawnand: atmel: fix possible object reference leak

[PATCH v5 1/3] mtd: rawnand: atmel: fix possible object reference leak

[Wen Yang]

of_find_device_by_node() takes a reference to the struct device
when it finds a match via get_device, there is no need to call
get_device() twice.
We also should make sure to drop the reference to the device
taken by of_find_device_by_node() on driver unbind.

Fixes: f88fc122cc34 ("mtd: nand: Cleanup/rework the atmel_nand driver")
Signed-off-by: Wen Yang <yellowriver2010@hotmail.com>
---
v5->v4: Add new line, add people in Cc and remove all Cc lines.
v4->v3: Avoid two times of calling grtform_get_drvdata()
v3->v2: Change the commit message.
v2->v1: Add missing Fixes tag.

 drivers/mtd/nand/raw/atmel/pmecc.c | 22 ++++++++++++++++------
 1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/drivers/mtd/nand/raw/atmel/pmecc.c b/drivers/mtd/nand/raw/atmel/pmecc.c
index 555a74e..97e47ea 100644
--- a/drivers/mtd/nand/raw/atmel/pmecc.c
+++ b/drivers/mtd/nand/raw/atmel/pmecc.c
@@ -876,23 +876,33 @@ static struct atmel_pmecc *atmel_pmecc_get_by_node(struct device *userdev,
 {
 	struct platform_device *pdev;
 	struct atmel_pmecc *pmecc, **ptr;
+	int ret;
 
 	pdev = of_find_device_by_node(np);
-	if (!pdev || !platform_get_drvdata(pdev))
+	if (!pdev)
 		return ERR_PTR(-EPROBE_DEFER);
 
-	ptr = devres_alloc(devm_atmel_pmecc_put, sizeof(*ptr), GFP_KERNEL);
-	if (!ptr)
-		return ERR_PTR(-ENOMEM);
-
-	get_device(&pdev->dev);
 	pmecc = platform_get_drvdata(pdev);
+	if (!pmecc) {
+		ret = -EPROBE_DEFER;
+		goto err_put_device;
+	}
+
+	ptr = devres_alloc(devm_atmel_pmecc_put, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr) {
+		ret = -ENOMEM;
+		goto err_put_device;
+	}
 
 	*ptr = pmecc;
 
 	devres_add(userdev, ptr);
 
 	return pmecc;
+
+err_put_device:
+	put_device(&pdev->dev);
+	return ERR_PTR(ret);
 }
 
 static const int atmel_pmecc_strengths[] = { 2, 4, 8, 12, 24, 32 };
-- 
2.7.4


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Re: [PATCH v5 1/3] mtd: rawnand: atmel: fix possible object reference leak

[Miquel Raynal]

Hi Wen,

Wen Yang <yellowriver2010@hotmail.com> wrote on Thu, 7 Feb 2019
11:56:48 +0000:

> of_find_device_by_node() takes a reference to the struct device
> when it finds a match via get_device, there is no need to call
> get_device() twice.
> We also should make sure to drop the reference to the device
> taken by of_find_device_by_node() on driver unbind.
> 
> Fixes: f88fc122cc34 ("mtd: nand: Cleanup/rework the atmel_nand driver")
> Signed-off-by: Wen Yang <yellowriver2010@hotmail.com>
> ---
> v5->v4: Add new line, add people in Cc and remove all Cc lines.
> v4->v3: Avoid two times of calling grtform_get_drvdata()
> v3->v2: Change the commit message.
> v2->v1: Add missing Fixes tag.
> 
>  drivers/mtd/nand/raw/atmel/pmecc.c | 22 ++++++++++++++++------
>  1 file changed, 16 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/atmel/pmecc.c b/drivers/mtd/nand/raw/atmel/pmecc.c
> index 555a74e..97e47ea 100644
> --- a/drivers/mtd/nand/raw/atmel/pmecc.c
> +++ b/drivers/mtd/nand/raw/atmel/pmecc.c
> @@ -876,23 +876,33 @@ static struct atmel_pmecc *atmel_pmecc_get_by_node(struct device *userdev,
>  {
>  	struct platform_device *pdev;
>  	struct atmel_pmecc *pmecc, **ptr;
> +	int ret;
>  
>  	pdev = of_find_device_by_node(np);
> -	if (!pdev || !platform_get_drvdata(pdev))
> +	if (!pdev)
>  		return ERR_PTR(-EPROBE_DEFER);
>  
> -	ptr = devres_alloc(devm_atmel_pmecc_put, sizeof(*ptr), GFP_KERNEL);
> -	if (!ptr)
> -		return ERR_PTR(-ENOMEM);
> -
> -	get_device(&pdev->dev);
>  	pmecc = platform_get_drvdata(pdev);
> +	if (!pmecc) {
> +		ret = -EPROBE_DEFER;
> +		goto err_put_device;
> +	}
> +
> +	ptr = devres_alloc(devm_atmel_pmecc_put, sizeof(*ptr), GFP_KERNEL);
> +	if (!ptr) {
> +		ret = -ENOMEM;
> +		goto err_put_device;
> +	}
>  
>  	*ptr = pmecc;
>  
>  	devres_add(userdev, ptr);
>  
>  	return pmecc;
> +
> +err_put_device:
> +	put_device(&pdev->dev);
> +	return ERR_PTR(ret);
>  }
>  
>  static const int atmel_pmecc_strengths[] = { 2, 4, 8, 12, 24, 32 };

Series applied to nand/next.


Thanks,
Miquèl

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