Re: [PATCH v2] watchdog: tangox_wdt: test clock rate to avoid division by 0

Guenter Roeck
2016-03-03T11:44:57Z

On 03/03/2016 12:24 AM, Wolfram Sang wrote:
> From: Wolfram Sang <wsa+renesas@sang-engineering.com>
>
> The clk API may return 0 on clk_get_rate, so we should check the result before
> using it as a divisor. For this, refactor the code to use a central
> error path.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
> drivers/watchdog/tangox_wdt.c | 14 ++++++++++----
> 1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/watchdog/tangox_wdt.c b/drivers/watchdog/tangox_wdt.c
> index 709c1ed6fd79b9..cfbed7e051b619 100644
> --- a/drivers/watchdog/tangox_wdt.c
> +++ b/drivers/watchdog/tangox_wdt.c
> @@ -139,6 +139,10 @@ static int tangox_wdt_probe(struct platform_device *pdev)
> return err;
>
> dev->clk_rate = clk_get_rate(dev->clk);
> + if (!dev->clk_rate) {
> + err = -EINVAL;
> + goto err;
> + }
>
> dev->wdt.parent = &pdev->dev;
> dev->wdt.info = &tangox_wdt_info;
> @@ -171,10 +175,8 @@ static int tangox_wdt_probe(struct platform_device *pdev)
> }
>
> err = watchdog_register_device(&dev->wdt);
> - if (err) {
> - clk_disable_unprepare(dev->clk);
> - return err;
> - }
> + if (err)
> + goto err;
>
> platform_set_drvdata(pdev, dev);
>
> @@ -187,6 +189,10 @@ static int tangox_wdt_probe(struct platform_device *pdev)
> dev_info(&pdev->dev, "SMP86xx/SMP87xx watchdog registered\n");
>
> return 0;
> +
> + err:
> + clk_disable_unprepare(dev->clk);
> + return err;
> }
>
> static int tangox_wdt_remove(struct platform_device *pdev)
>