linux-kernel - [PATCH AUTOSEL 6.10 098/197] fbdev: efifb: Register sysfs groups through driver core

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Message-ID: <20240925115823.1303019-98-sashal@kernel.org>
Date: Wed, 25 Sep 2024 07:51:57 -0400
From: Sasha Levin <sashal@...nel.org>
To: linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Cc: Thomas Weißschuh <linux@...ssschuh.net>,
	Helge Deller <deller@....de>,
	Sasha Levin <sashal@...nel.org>,
	pjones@...hat.com,
	linux-fbdev@...r.kernel.org,
	dri-devel@...ts.freedesktop.org
Subject: [PATCH AUTOSEL 6.10 098/197] fbdev: efifb: Register sysfs groups through driver core

From: Thomas Weißschuh <linux@...ssschuh.net>

[ Upstream commit 95cdd538e0e5677efbdf8aade04ec098ab98f457 ]

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>
Signed-off-by: Helge Deller <deller@....de>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 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 8dd82afb3452b..595b8e27bea66 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,
-- 
2.43.0