[PATCH] hwmon: (w83795) Clamp fan control times before rounding

[PATCH] hwmon: (w83795) Clamp fan control times before rounding

[Zhu Jun]

From: zhujun <zhujun2@cmss.chinamobile.com>

time_to_reg() adds 50 before clamping the result. An unsigned long close
to ULONG_MAX wraps, so an excessive stop time can select zero rather
than the maximum. The same conversion is used for fan speed transition
times.

Clamp to the maximum representable duration before adding the rounding
adjustment.

Fixes: 792d376b4f3f ("hwmon: New driver for the W83795G/ADG monitoring chips")
---
Validation: x86-64 and i386 driver objects built with W=1.
Source-extracted boundary tests passed on 32-bit and 64-bit;
the corresponding test fails on the base revision. I/O is mocked.
No physical sensor hardware or booted-kernel test was available.
OpenAI Codex assisted analysis, code, tests and changelog drafting.
The human submitter must review and add their Signed-off-by.

 drivers/hwmon/w83795.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/w83795.c b/drivers/hwmon/w83795.c
index 96fbb0a5006f..9b0ef0c8c5b7 100644
--- a/drivers/hwmon/w83795.c
+++ b/drivers/hwmon/w83795.c
@@ -260,7 +260,7 @@ static inline unsigned long time_from_reg(u8 reg)
 
 static inline u8 time_to_reg(unsigned long val)
 {
-	return clamp_val((val + 50) / 100, 0, 0xff);
+	return (min(val, 25500UL) + 50) / 100;
 }
 
 static inline long temp_from_reg(s8 reg)

base-commit: 7475ea8b58616b33c04afb976cf0fbaad9dd63fb
-- 
2.51.0

Re: [PATCH] hwmon: (w83795) Clamp fan control times before rounding

[sashiko-bot]

> From: zhujun <zhujun2@cmss.chinamobile.com>
> 
> time_to_reg() adds 50 before clamping the result. An unsigned long close
> to ULONG_MAX wraps, so an excessive stop time can select zero rather
> than the maximum. The same conversion is used for fan speed transition
> times.
> 
> Clamp to the maximum representable duration before adding the rounding
> adjustment.
> 
> Fixes: 792d376b4f3f ("hwmon: New driver for the W83795G/ADG monitoring chips")

Sashiko has reviewed this patch and found no issues.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261109093722.5508-1-zhujun2@cmss.chinamobile.com?part=1

[PATCH] hwmon: (w83795) Clamp fan control times before rounding

[Zhu Jun]

time_to_reg() adds 50 before clamping the result. An unsigned long close
to ULONG_MAX wraps, so an excessive stop time can select zero rather
than the maximum. The same conversion is used for fan speed transition
times.

Clamp to the maximum representable duration before adding the rounding
adjustment.

Fixes: 792d376b4f3f ("hwmon: New driver for the W83795G/ADG monitoring chips")
Signed-off-by: Zhu Jun <zhujun2@cmss.chinamobile.com>
---
 drivers/hwmon/w83795.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/w83795.c b/drivers/hwmon/w83795.c
index 96fbb0a5006f..9b0ef0c8c5b7 100644
--- a/drivers/hwmon/w83795.c
+++ b/drivers/hwmon/w83795.c
@@ -260,7 +260,7 @@ static inline unsigned long time_from_reg(u8 reg)
 
 static inline u8 time_to_reg(unsigned long val)
 {
-	return clamp_val((val + 50) / 100, 0, 0xff);
+	return (min(val, 25500UL) + 50) / 100;
 }
 
 static inline long temp_from_reg(s8 reg)
-- 
2.51.0

Re: [PATCH] hwmon: (w83795) Clamp fan control times before rounding

[sashiko-bot]

> time_to_reg() adds 50 before clamping the result. An unsigned long close
> to ULONG_MAX wraps, so an excessive stop time can select zero rather
> than the maximum. The same conversion is used for fan speed transition
> times.
> 
> Clamp to the maximum representable duration before adding the rounding
> adjustment.
> 
> Fixes: 792d376b4f3f ("hwmon: New driver for the W83795G/ADG monitoring chips")
> Signed-off-by: Zhu Jun <zhujun2@cmss.chinamobile.com>

Sashiko has reviewed this patch and found no issues.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261111065123.17512-1-zhujun2@cmss.chinamobile.com?part=1