[PATCH v4 1/3] mtd: rawnand: atmel: fix possible object reference leak

[PATCH v4 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>
Suggested-by: Boris Brezillon <bbrezillon@kernel.org>
Reviewed-by: Boris Brezillon <bbrezillon@kernel.org>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Tudor Ambarus <tudor.ambarus@microchip.com>
Cc: Boris Brezillon <bbrezillon@kernel.org>
Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
Cc: linux-mtd@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
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 | 21 +++++++++++++++------
 1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/drivers/mtd/nand/raw/atmel/pmecc.c b/drivers/mtd/nand/raw/atmel/pmecc.c
index 555a74e..9d39978 100644
--- a/drivers/mtd/nand/raw/atmel/pmecc.c
+++ b/drivers/mtd/nand/raw/atmel/pmecc.c
@@ -876,23 +876,32 @@ 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);
+	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)
-		return ERR_PTR(-ENOMEM);
-
-	get_device(&pdev->dev);
-	pmecc = platform_get_drvdata(pdev);
+	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 v4 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
03:50:55 +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>
> Suggested-by: Boris Brezillon <bbrezillon@kernel.org>

Suggested-by means that Boris suggested you to write this patch in the
first place. If he just made a review, you should drop this tag.

> Reviewed-by: Boris Brezillon <bbrezillon@kernel.org>
> Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>

None of us gave our Reviewed-by officially, so you can drop these lines.

> Acked-by: Miquel Raynal <miquel.raynal@bootlin.com>

I gave my Acked-by because I though Boris would take the patch, but
actually he will not, so you can drop the Ack.

> Cc: Tudor Ambarus <tudor.ambarus@microchip.com>
> Cc: Boris Brezillon <bbrezillon@kernel.org>
> Cc: Miquel Raynal <miquel.raynal@bootlin.com>
> Cc: Richard Weinberger <richard@nod.at>
> Cc: David Woodhouse <dwmw2@infradead.org>
> Cc: Brian Norris <computersforpeace@gmail.com>
> Cc: Marek Vasut <marek.vasut@gmail.com>
> Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
> Cc: Ludovic Desroches <ludovic.desroches@microchip.com>
> Cc: linux-mtd@lists.infradead.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org

Please add people in Cc when you send the series and remove all these
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 | 21 +++++++++++++++------
>  1 file changed, 15 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/atmel/pmecc.c b/drivers/mtd/nand/raw/atmel/pmecc.c
> index 555a74e..9d39978 100644
> --- a/drivers/mtd/nand/raw/atmel/pmecc.c
> +++ b/drivers/mtd/nand/raw/atmel/pmecc.c
> @@ -876,23 +876,32 @@ 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);

New line missing here

> +	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)
> -		return ERR_PTR(-ENOMEM);
> -
> -	get_device(&pdev->dev);
> -	pmecc = platform_get_drvdata(pdev);
> +	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 };

All the comments apply to the two other patches.

Otherwise looks good.


Thanks,
Miquèl

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