[PATCH AUTOSEL 6.11 114/244] fbdev: efifb: Register sysfs groups through driver core

Sasha Levin
2024-09-25T11:42:14Z

From: Thomas Weißschuh <linux@weissschuh.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@weissschuh.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.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