Re: [net-next,v2,3/6] eth: fbnic: cache hwmon sensor readings

On Thu, 03 Sep 2026 03:24:09 +0000 netdev-bot+sashiko@kernel.org wrote:

quoted

@@ -25,26 +26,32 @@ static umode_t fbnic_hwmon_is_visible(const void *drvdata,
+	if (*cached != FBNIC_SENSOR_NO_DATA &&
+	    time_is_after_eq_jiffies(cache->last_read)) {
+		*val = *cached;
+		return 0;
 	}  

[Severity: Medium]
The cache validity test uses the wrong end of the jiffies helper
family. time_is_after_eq_jiffies(a) expands to
time_before_eq(jiffies, a), i.e. it is meant to be applied to a
deadline that lies in the future, but cache->last_read is a timestamp
in the past (it is assigned plain jiffies right after the TSENE
response is parsed). It happens to give the intended "valid for the
remainder of the current jiffy" behaviour only because
time_before_eq() is a signed difference that goes negative one tick
later.

This may be theoretical but it's also easy enough to fix.
There's no reason for us to use time_is_after() when
we want an exact comparison