Re: [PATCH 2/2] hwmon: (asus_rog_ryujin) Add pwm1_enable for the Ryujin III pump

[Zac Lanzon <lanzonza@gmail.com>]

On Sun, Sep 27, 2026 at 12:19:31PM +0000, sashiko-bot@kernel.org wrote:
> > +	now = jiffies;
> > +	next = priv->source_changed + msecs_to_jiffies(RYUJIN_SOURCE_CHANGE_INTERVAL);
> > +	if (time_before(now, next))
> > +		msleep(jiffies_to_msecs(next - now));
>
> [Severity: Medium]
> Is there a risk of a massive unintended sleep here due to a jiffies
> wrap-around?
>
> On 32-bit systems, if the elapsed time since priv->source_changed exceeds
> 2^31 jiffies (for example, if there are no source changes for 24.8 days at
> HZ=1000), time_before() can wrap and return true. This would feed a very
> large wrapped value from next - now into msleep(), causing a thread hang
> when a write to the cooler duty attribute is attempted.

Right. v2 computes the elapsed time with an unsigned subtraction, so the
wait can never exceed RYUJIN_SOURCE_CHANGE_INTERVAL:

	unsigned long interval = msecs_to_jiffies(RYUJIN_SOURCE_CHANGE_INTERVAL);

	elapsed = jiffies - priv->source_changed;
	if (elapsed < interval)
		msleep(jiffies_to_msecs(interval - elapsed));

Patch 1 has no timing code and is unchanged. v2 follows tomorrow,
retested on the RYUJIN III 360.

Thanks,
Zac