Re: [PATCH] drm: renesas: rz-du: mipi-dsi: Drop duplicate platform_set_drvdata() call

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found no new issues
in this patch, but noticed 1 related pre-existing issue it does not
introduce:
- [High] drm: renesas: rz-du: null pointer dereference in
  rzg2l_mipi_dsi_probe() [1]
--

commit dcaf0e503b70614276db2fd071bf963a09140504
Author: John Madieu <john.madieu.xa@bp.renesas.com>

drm: renesas: rz-du: mipi-dsi: Drop duplicate platform_set_drvdata() call

This commit removes a redundant platform_set_drvdata() call in
rzg2l_mipi_dsi_probe().

> diff --git a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> index 5b257f5adf06c..985d6e02203c1 100644
> --- a/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> +++ b/drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c
> @@ -1576,8 +1576,6 @@ static int rzg2l_mipi_dsi_probe(struct platform_device *pdev)
>  	if (!dsi->dcs_buf_virt)
>  		return -ENOMEM;
>  
> -	platform_set_drvdata(pdev, dsi);
> -
>  	ret = rzg2l_mipi_dsi_pwrrdy_init(dsi);
>  	if (ret)
>  		return ret;

[Severity: High]
This problem wasn't introduced by this patch, but can a NULL pointer
dereference occur in rzg2l_mipi_dsi_probe() [1] if the driver is
manually bound via sysfs without matching device tree data?

drivers/gpu/drm/renesas/rz-du/rzg2l_mipi_dsi.c:rzg2l_mipi_dsi_probe() {
	...
	dsi->info = of_device_get_match_data(&pdev->dev);
	...
	ret = rzg2l_mipi_dsi_pwrrdy_init(dsi);
	...
	ret = dsi->info->dphy_init(dsi, 80000000ULL * MILLI);
	...
}

of_device_get_match_data() returns NULL when no match is found, and
dsi->info is later dereferenced without a NULL check in
rzg2l_mipi_dsi_pwrrdy_init() and when calling dsi->info->dphy_init().

[1] https://sashiko.dev/#/bug/linux-14b243a7-c808-4384-b0dc-3416dc888b2a

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261110114622.229608-1-prabhakar.mahadev-lad.rj@bp.renesas.com?part=1