Re: [PATCH v5 2/5] watchdog: w83627hf_wdt: Convert to platform driver model

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] watchdog: w83627hf_wdt: format truncation warning in wdt_probe()
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commit a96b55145c68318e10b7deaae2c19abda6f0df61
Author: Paul Louvel <paul.louvel@bootlin.com>

watchdog: w83627hf_wdt: Convert to platform driver model

This commit converts the w83627hf_wdt driver to use the platform driver
model with device-managed resources and adds error logging during probe.

> diff --git a/drivers/watchdog/w83627hf_wdt.c b/drivers/watchdog/w83627hf_wdt.c
> index fa1808a4c6c88..96ea278e45c4e 100644
> --- a/drivers/watchdog/w83627hf_wdt.c
> +++ b/drivers/watchdog/w83627hf_wdt.c
[ ... ]
> @@ -462,6 +456,58 @@ static int wdt_find(int addr)
>  	return ret;
>  }
>  
> +static int wdt_probe(struct platform_device *pdev)
> +{
> +	const struct platform_device_id *id = platform_get_device_id(pdev);
> +	struct device *dev = &pdev->dev;
> +	struct watchdog_device *wdd;
> +	struct w83627hf_data *data;
> +	enum chips chip;
> +	int ret;
> +
> +	dev_info(dev, "WDT driver initialising\n");
> +
> +	if (!id)
> +		return dev_err_probe(dev, -EINVAL, "failed to get chip id\n");
> +
> +	chip = id->driver_data;
> +
> +	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	data->info.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE;
> +	snprintf(data->info.identity, sizeof(data->info.identity), "%s Watchdog",
> +		 id->name);

[Severity: Low]
Does this unchecked snprintf() call in wdt_probe() trigger a
-Wformat-truncation warning when building with GCC under W=1?

In include/linux/mod_devicetable.h, id->name is a 24-byte array:

    #define PLATFORM_NAME_SIZE	24
    ...
    struct platform_device_id {
    	char name[PLATFORM_NAME_SIZE];
    	kernel_ulong_t driver_data;
    };

And in include/uapi/linux/watchdog.h, data->info.identity is 32 bytes:

    struct watchdog_info {
    	__u32 options;		/* Options the card/driver supports */
    	__u32 firmware_version;	/* Firmware version of the card */
    	__u8  identity[32];	/* Identity of the board */
    };

Because id is retrieved via platform_get_device_id(pdev), GCC cannot narrow
id->name to the string literals in wdt_ids[] and sees up to 23 characters
plus " Watchdog" (33 bytes including NUL) being formatted into the 32-byte
data->info.identity buffer.

Would it be better to use scnprintf() here instead of snprintf() to avoid
the truncation warning?

[ ... ]

$>

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261020-w83627hf_wdt-improvements-v5-0-90b226684fc7@bootlin.com?part=2