Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1575460 > unrolled thread

[PATCH 2/2] spi: s3c64xx: fix potential division by zero

Back to article view | Back to linux.kernel

This discussion starts older than the indexed window; earlier articles aren't shown. The article labeled Started by below is the oldest one visible, not the original post.

Contents

  [PATCH 2/2] spi: s3c64xx: fix potential division by zero Andi Shyti <andi.shyti@samsung.com> - 2017-02-07 09:20 +0100
    Re: [PATCH 2/2] spi: s3c64xx: fix potential division by zero Krzysztof Kozlowski <krzk@kernel.org> - 2017-02-07 21:50 +0100
      Re: [PATCH 2/2] spi: s3c64xx: fix potential division by zero Andi Shyti <andi.shyti@samsung.com> - 2017-02-08 06:40 +0100

#1575460 — [PATCH 2/2] spi: s3c64xx: fix potential division by zero

Even though it's quite unlikely to happen in this particular
case, clk_get_rate can return '0' if sdd->src_clk is not set
properly. In that case we would have a clear division by '0'.

Check the return value of clk_get_rate and fail in case it
returns '0'.

This patch fixes '1397922 Division or modulo by zero' from
scan.coverity.com

Signed-off-by: Andi Shyti <andi.shyti@samsung.com>
---
 drivers/spi/spi-s3c64xx.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index f6ea9ae047ec..a2ec07f44e33 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -811,6 +811,8 @@ static int s3c64xx_spi_setup(struct spi_device *spi)
 
 		/* Max possible */
 		speed = clk_get_rate(sdd->src_clk) / 2 / (0 + 1);
+		if (!speed)
+			goto setup_exit;
 
 		if (spi->max_speed_hz > speed)
 			spi->max_speed_hz = speed;
-- 
2.11.0

[toc] | [next] | [standalone]

#1576044

On Tue, Feb 07, 2017 at 05:10:25PM +0900, Andi Shyti wrote:
> Even though it's quite unlikely to happen in this particular
> case, clk_get_rate can return '0' if sdd->src_clk is not set
> properly. In that case we would have a clear division by '0'.
> 

I do not think it is possible.
	if (IS_ERR(sdd->src_clk)) {
		ret = PTR_ERR(sdd->src_clk);
		goto err_deref_master;
	}

> Check the return value of clk_get_rate and fail in case it
> returns '0'.
> 
> This patch fixes '1397922 Division or modulo by zero' from
> scan.coverity.com

It is a false positive.

Best regards,
Krzysztof

> 
> Signed-off-by: Andi Shyti <andi.shyti@samsung.com>
> ---
>  drivers/spi/spi-s3c64xx.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
> index f6ea9ae047ec..a2ec07f44e33 100644
> --- a/drivers/spi/spi-s3c64xx.c
> +++ b/drivers/spi/spi-s3c64xx.c
> @@ -811,6 +811,8 @@ static int s3c64xx_spi_setup(struct spi_device *spi)
>  
>  		/* Max possible */
>  		speed = clk_get_rate(sdd->src_clk) / 2 / (0 + 1);
> +		if (!speed)
> +			goto setup_exit;
>  
>  		if (spi->max_speed_hz > speed)
>  			spi->max_speed_hz = speed;
> -- 
> 2.11.0
> 

[toc] | [prev] | [next] | [standalone]

#1576285

> > This patch fixes '1397922 Division or modulo by zero' from
> > scan.coverity.com
> 
> It is a false positive.

Yes... sorry for these two spam/patches... they are just fast
after holiday "fixes"... please ignore them.

Andi

[toc] | [prev] | [standalone]

Back to top | Article view | linux.kernel

csiph-web