Hi Rasmus,

(add Pali to Cc)

On 27.09.22 09:45, Rasmus Villemoes wrote:

The udelay() function in lib/time.c contains a WATCHDOG_RESET() call. The only reason this doesn't lead to a catastrophic infinite recursion is due to the rate-limiting in wdt-uclass.c:

if (time_after_eq(now, priv->next_reset)) {
	priv->next_reset = now + priv->reset_period;
	wdt_reset(dev);
}

But this would fall apart if ->next_reset was updated after calling the device's reset method.

This is needlessly fragile, and it's easy enough to avoid that recursion in the first place by just using __udelay() directly.

Signed-off-by: Rasmus Villemoes rasmus.villemoes@prevas.dk

drivers/watchdog/gpio_wdt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/watchdog/gpio_wdt.c b/drivers/watchdog/gpio_wdt.c index fe06ec8cc9..2920c2c751 100644 --- a/drivers/watchdog/gpio_wdt.c +++ b/drivers/watchdog/gpio_wdt.c @@ -31,7 +31,7 @@ static int gpio_wdt_reset(struct udevice *dev) case HW_ALGO_LEVEL: /* Pulse */ dm_gpio_set_value(&priv->gpio, 1);

• udelay(1);
  

• __udelay(1);
  

  dm_gpio_set_value(&priv->gpio, 0); break; }

Yes, good catch:

Reviewed-by: Stefan Roese sr@denx.de

The max6370_wdt.c driver has the same problem AFAICT. Pali, could you please take a look a this?

Thanks, Stefan

On 27.09.22 09:45, Rasmus Villemoes wrote:

The udelay() function in lib/time.c contains a WATCHDOG_RESET() call. The only reason this doesn't lead to a catastrophic infinite recursion is due to the rate-limiting in wdt-uclass.c:

if (time_after_eq(now, priv->next_reset)) {
	priv->next_reset = now + priv->reset_period;
	wdt_reset(dev);
}

But this would fall apart if ->next_reset was updated after calling the device's reset method.

This is needlessly fragile, and it's easy enough to avoid that recursion in the first place by just using __udelay() directly.

Signed-off-by: Rasmus Villemoes rasmus.villemoes@prevas.dk

Applied to u-boot-watchdog/master

Thanks, Stefan

---

drivers/watchdog/gpio_wdt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/watchdog/gpio_wdt.c b/drivers/watchdog/gpio_wdt.c index fe06ec8cc9..2920c2c751 100644 --- a/drivers/watchdog/gpio_wdt.c +++ b/drivers/watchdog/gpio_wdt.c @@ -31,7 +31,7 @@ static int gpio_wdt_reset(struct udevice *dev) case HW_ALGO_LEVEL: /* Pulse */ dm_gpio_set_value(&priv->gpio, 1);

• udelay(1);
  

• __udelay(1);
  

  dm_gpio_set_value(&priv->gpio, 0); break; }

Viele Grüße, Stefan Roese