fbdev: efifb: Register sysfs groups through driver core

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>

diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c
index 8dd82afb3452ba8d381968e84f05490a7ea2843d..595b8e27bea66d8b530e8a407cd6db96598163cc 100644 (file)
--- 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,