linux-kernel - Re: [PATCH 2/5] fbdev/efifb: Register sysfs groups through driver core

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Message-ID: <d1cab5f1-2b3a-413a-8ccf-3152fd8b95df@gmx.de>
Date: Wed, 28 Aug 2024 19:50:29 +0200
From: Helge Deller <deller@....de>
To: Thomas Weißschuh <linux@...ssschuh.net>,
 Peter Jones <pjones@...hat.com>, Daniel Vetter <daniel@...ll.ch>
Cc: linux-fbdev@...r.kernel.org, dri-devel@...ts.freedesktop.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/5] fbdev/efifb: Register sysfs groups through driver
 core

On 8/27/24 17:25, Thomas Weißschuh wrote:
> The driver core can register and cleanup sysfs groups already.
> Make use of that functionality to simplify the error handling and
> cleanup.
>
> Also avoid a UAF race during unregistering where the sysctl attributes
> were usable after the info struct was freed.
>
> Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>

I've added your patches #2, #3, #4 and #5 of this series to the fbdev git tree.
I tend to not take patch #1 as already explained there...

Thanks!
Helge



> ---
>   drivers/video/fbdev/efifb.c | 11 ++---------
>   1 file changed, 2 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c
> index 8bfe0ccbc67a..d36b95856dd0 100644
> --- a/drivers/video/fbdev/efifb.c
> +++ b/drivers/video/fbdev/efifb.c
> @@ -561,15 +561,10 @@ static int efifb_probe(struct platform_device *dev)
>   		break;
>   	}
>
> -	err = sysfs_create_groups(&dev->dev.kobj, efifb_groups);
> -	if (err) {
> -		pr_err("efifb: cannot add sysfs attrs\n");
> -		goto err_unmap;
> -	}
>   	err = fb_alloc_cmap(&info->cmap, 256, 0);
>   	if (err < 0) {
>   		pr_err("efifb: cannot allocate colormap\n");
> -		goto err_groups;
> +		goto err_unmap;
>   	}
>
>   	err = devm_aperture_acquire_for_platform_device(dev, par->base, par->size);
> @@ -587,8 +582,6 @@ static int efifb_probe(struct platform_device *dev)
>
>   err_fb_dealloc_cmap:
>   	fb_dealloc_cmap(&info->cmap);
> -err_groups:
> -	sysfs_remove_groups(&dev->dev.kobj, efifb_groups);
>   err_unmap:
>   	if (mem_flags & (EFI_MEMORY_UC | EFI_MEMORY_WC))
>   		iounmap(info->screen_base);
> @@ -608,12 +601,12 @@ static void efifb_remove(struct platform_device *pdev)
>
>   	/* efifb_destroy takes care of info cleanup */
>   	unregister_framebuffer(info);
> -	sysfs_remove_groups(&pdev->dev.kobj, efifb_groups);
>   }
>
>   static struct platform_driver efifb_driver = {
>   	.driver = {
>   		.name = "efi-framebuffer",
> +		.dev_groups = efifb_groups,
>   	},
>   	.probe = efifb_probe,
>   	.remove_new = efifb_remove,
>