[PATCH] spi/imx: prevent NULL pointer dereference in spi_imx_probe()

[PATCH] spi/imx: prevent NULL pointer dereference in spi_imx_probe()

[Lothar Waßmann]

When no platform_data is present and either 'spi-num-chipselects' is
not defined in the DT or 'cs-gpios' has less entries than
'spi-num-chipselects' specifies, the NULL platform_data pointer is
being dereferenced.

Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
---
 drivers/spi/spi-imx.c |   10 +++++++---
 1 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
index 373f4ff..570f220 100644
--- a/drivers/spi/spi-imx.c
+++ b/drivers/spi/spi-imx.c
@@ -766,8 +766,12 @@ static int __devinit spi_imx_probe(struct platform_device *pdev)
 	}
 
 	ret = of_property_read_u32(np, "fsl,spi-num-chipselects", &num_cs);
-	if (ret < 0)
-		num_cs = mxc_platform_info->num_chipselect;
+	if (ret < 0) {
+		if (mxc_platform_info)
+			num_cs = mxc_platform_info->num_chipselect;
+		else
+			return ret;
+	}
 
 	master = spi_alloc_master(&pdev->dev,
 			sizeof(struct spi_imx_data) + sizeof(int) * num_cs);
@@ -784,7 +788,7 @@ static int __devinit spi_imx_probe(struct platform_device *pdev)
 
 	for (i = 0; i < master->num_chipselect; i++) {
 		int cs_gpio = of_get_named_gpio(np, "cs-gpios", i);
-		if (cs_gpio < 0)
+		if (cs_gpio < 0 && mxc_platform_info)
 			cs_gpio = mxc_platform_info->chipselect[i];
 
 		spi_imx->chipselect[i] = cs_gpio;
-- 
1.7.2.5

Re: [PATCH] spi/imx: prevent NULL pointer dereference in spi_imx_probe()

[Grant Likely]

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On Tue,  3 Apr 2012 15:03:44 +0200, Lothar Waßmann <LW-bxm8fMRDkQLDiMYJYoSAnRvVK+yQ3ZXh@public.gmane.org> wrote:
> When no platform_data is present and either 'spi-num-chipselects' is
> not defined in the DT or 'cs-gpios' has less entries than
> 'spi-num-chipselects' specifies, the NULL platform_data pointer is
> being dereferenced.
> 
> Signed-off-by: Lothar Waßmann <LW-bxm8fMRDkQLDiMYJYoSAnRvVK+yQ3ZXh@public.gmane.org>

Applied, thanks.

g.

> ---
>  drivers/spi/spi-imx.c |   10 +++++++---
>  1 files changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c
> index 373f4ff..570f220 100644
> --- a/drivers/spi/spi-imx.c
> +++ b/drivers/spi/spi-imx.c
> @@ -766,8 +766,12 @@ static int __devinit spi_imx_probe(struct platform_device *pdev)
>  	}
>  
>  	ret = of_property_read_u32(np, "fsl,spi-num-chipselects", &num_cs);
> -	if (ret < 0)
> -		num_cs = mxc_platform_info->num_chipselect;
> +	if (ret < 0) {
> +		if (mxc_platform_info)
> +			num_cs = mxc_platform_info->num_chipselect;
> +		else
> +			return ret;
> +	}
>  
>  	master = spi_alloc_master(&pdev->dev,
>  			sizeof(struct spi_imx_data) + sizeof(int) * num_cs);
> @@ -784,7 +788,7 @@ static int __devinit spi_imx_probe(struct platform_device *pdev)
>  
>  	for (i = 0; i < master->num_chipselect; i++) {
>  		int cs_gpio = of_get_named_gpio(np, "cs-gpios", i);
> -		if (cs_gpio < 0)
> +		if (cs_gpio < 0 && mxc_platform_info)
>  			cs_gpio = mxc_platform_info->chipselect[i];
>  
>  		spi_imx->chipselect[i] = cs_gpio;
> -- 
> 1.7.2.5
> 
> --
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-- 
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies,Ltd.


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