Re: [PATCH v1 2/2] Input: uinput: align UI_ABS_SETUP validation with uapi docs

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Critical] Adding a strict minimum == 0 validation for ABS_MT_SLOT breaks backward compatibility by rejecting previously accepted configurations.
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commit 12ce67adcfd7a78984b09163e522a86103b65a3c
Author: Iván Ezequiel Rodriguez <ivanrwcm25@gmail.com>

Input: uinput: align UI_ABS_SETUP validation with uapi docs

This commit updates uinput to align with UAPI documentation by returning
-EINVAL for out-of-range axis codes. It also adds a strict validation check
to reject ABS_MT_SLOT configurations if the minimum value is not zero.

> diff --git a/drivers/input/misc/uinput.c b/drivers/input/misc/uinput.c
> index d32fa4b508fc5..e05c80182252d 100644
> --- a/drivers/input/misc/uinput.c
> +++ b/drivers/input/misc/uinput.c
> @@ -424,6 +424,13 @@ static int uinput_validate_absinfo(struct input_dev *dev, unsigned int code,
>  	min = abs->minimum;
>  	max = abs->maximum;
>  
> +	if (code == ABS_MT_SLOT && min != 0) {
> +		printk(KERN_DEBUG
> +		       "%s: abs[%02x] minimum must be 0\n",
> +		       UINPUT_NAME, code);
> +		return -EINVAL;
> +	}

[Severity: Critical]
Does adding this strict validation break backward compatibility for existing
userspace applications? 

Applications that historically passed non-zero minimum values for ABS_MT_SLOT
(which the kernel silently accepted and later clamped to 0) will now fail to
initialize uinput devices, receiving -EINVAL during the UI_ABS_SETUP ioctl.
This introduces a userspace regression by rejecting previously accepted 
configurations.

[ ... ]

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Sashiko AI review · https://sashiko.dev/#/patchset/20260831152156.166514-1-ivanrwcm25@gmail.com?part=2