Re: [PATCH 2/3] drm/sysfb: simpledrm: Improve panel-size validation

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Uninitialized stack variable `value` is printed in `drm_dbg()` when `of_property_read_u32()` fails.
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commit a1ba4b62fd041b3fc66d9ae1c41a47b859017d1c
Author: Thomas Zimmermann <tzimmermann@suse.de>

drm/sysfb: simpledrm: Improve panel-size validation

This commit validates the panel size from the device-tree node against
the limitations of struct drm_display_mode and fails transparently on
errors without warning.

Cc: stable@vger.kernel.org # v6.4+

> diff --git a/drivers/gpu/drm/sysfb/simpledrm.c b/drivers/gpu/drm/sysfb/simpledrm.c
> index 03bd19fadccd5..5c1db0785d926 100644
> --- a/drivers/gpu/drm/sysfb/simpledrm.c
> +++ b/drivers/gpu/drm/sysfb/simpledrm.c
> @@ -200,6 +200,35 @@ simplefb_get_memory_of(struct drm_device *dev, struct device_node *of_node)
>  	return res;
>  }
>  
> +static u16
> +__simplefb_get_panel_size_mm_of(struct drm_device *dev, struct device_node *of_panel_node,
> +				const char *name)
> +{
> +	int ret;
> +	u32 value;
> +
> +	ret = of_property_read_u32(of_panel_node, name, &value);
> +	if (ret || value > U16_MAX) {
> +		drm_dbg(dev, "simplefb: cannot parse panel %s: value %u, error %d\n",
> +			name, value, ret);

[Severity: Low]
Does this code print an uninitialized stack variable when
of_property_read_u32() fails?

If the property is missing from the device tree or another error occurs,
of_property_read_u32() will return a non-zero error code and leave the
value parameter untouched. When this happens, the uninitialized stack
memory will be unconditionally passed to drm_dbg() for printing.

> +		return 0; /* not an error, simply ignore */
> +	}
> +
> +	return value;
> +}

[ ... ]

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Sashiko AI review · https://sashiko.dev/#/patchset/20260619135847.309664-1-tzimmermann@suse.de?part=2