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From: "Poosa, Karthik" <karthik.poosa@intel.com>
To: Mallesh Koujalagi <mallesh.koujalagi@intel.com>,
	<intel-xe@lists.freedesktop.org>, <rodrigo.vivi@intel.com>,
	<matthew.brost@intel.com>
Cc: <anshuman.gupta@intel.com>, <badal.nilawar@intel.com>,
	<vinay.belgaumkar@intel.com>, <riana.tauro@intel.com>,
	<sk.anirban@intel.com>, <raag.jadav@intel.com>,
	<aravind.iddamsetty@linux.intel.com>,
	<jani.nikula@linux.intel.com>
Subject: Re: [PATCH v2] drm/xe/hwmon: Use overflows_type() for temperature range check
Date: Mon, 26 Oct 2026 17:04:35 +0530	[thread overview]
Message-ID: <e4839979-963a-4298-9fef-5f4486a67442@intel.com> (raw)
In-Reply-To: <20261023143632.461084-2-mallesh.koujalagi@intel.com>


On 23-10-2026 20:06, Mallesh Koujalagi wrote:
> The temperature value is calculated as an s64 before being stored
> in a long. Check whether the value fits in the target type using
> overflows_type() instead of comparing against LONG_MAX directly.
>
> This keeps the overflow check correct on both 32-bit and 64-bit
> systems and avoids architecture-specific handling.
>
> Fixes: 24ec15d64617 ("drm/xe/hwmon: Decode CRI temperature registers as IEEE-754")
> Signed-off-by: Mallesh Koujalagi <mallesh.koujalagi@intel.com>
> ---
> v2:
> - Use overflows_type(), instead of #ifdef. (Jani)
> ---
>   drivers/gpu/drm/xe/xe_hwmon.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_hwmon.c b/drivers/gpu/drm/xe/xe_hwmon.c
> index 42acfeb8818c..515b288f18e5 100644
> --- a/drivers/gpu/drm/xe/xe_hwmon.c
> +++ b/drivers/gpu/drm/xe/xe_hwmon.c
> @@ -6,6 +6,7 @@
>   #include <linux/hwmon-sysfs.h>
>   #include <linux/hwmon.h>
>   #include <linux/jiffies.h>
> +#include <linux/overflow.h>
>   #include <linux/types.h>
>   #include <linux/units.h>
>   
> @@ -1322,8 +1323,8 @@ static int xe_hwmon_temperature_decode(u32 reg_val, long *temperature)
>   		value = 0;
>   	}
>   
> -	/* Ensure the magnitude fits in long, which is 32-bit on some arches. */
> -	if (value > LONG_MAX)
> +	/* Ensure the decoded value fits in a long. */
> +	if (overflows_type(value, *temperature))
Is this change addressing an issue reported by a static analysis tool ?

|LONG_MAX| already reflects the platform-specific size of |long|, so is 
this still needed ?

>   		return -ERANGE;
>   
>   	if (reg_val & IEEE754_SIGN)

  parent reply	other threads:[~2026-10-26 11:35 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-23 14:36 [PATCH v2] drm/xe/hwmon: Use overflows_type() for temperature range check Mallesh Koujalagi
2026-10-23 14:45 ` ✓ CI.KUnit: success for " Patchwork
2026-10-23 15:26 ` ✓ Xe.CI.BAT: " Patchwork
2026-10-23 21:40 ` ✓ Xe.CI.FULL: " Patchwork
2026-10-26 11:34 ` Poosa, Karthik [this message]
2026-10-26 12:36   ` [PATCH v2] " Mallesh, Koujalagi
2026-10-28  5:26     ` Poosa, Karthik
2026-10-27 16:08 ` Jani Nikula

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