f2fs: fix uninitialized kobject put in f2fs_init_sysfs()

commit b635f2e upstream.

In f2fs_init_sysfs(), all failure paths after kset_register() jump to
put_kobject, which unconditionally releases both f2fs_tune and
f2fs_feat.

If kobject_init_and_add(&f2fs_feat, ...) fails, f2fs_tune has not been
initialized yet, so calling kobject_put(&f2fs_tune) is invalid.

Fix this by splitting the unwind path so each error path only releases
objects that were successfully initialized.

Fixes: a907f3a ("f2fs: add a sysfs entry to reclaim POSIX_FADV_NOREUSE pages")
Cc: stable@vger.kernel.org
Signed-off-by: Guangshuo Li <lgs201920130244@gmail.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: lgs2513

fs/f2fs/sysfs.c

@@ -1984,24 +1984,26 @@ int __init f2fs_init_sysfs(void)
 	ret = kobject_init_and_add(&f2fs_feat, &f2fs_feat_ktype,
 				   NULL, "features");
 	if (ret)
-		goto put_kobject;
+		goto unregister_kset;
 
 	ret = kobject_init_and_add(&f2fs_tune, &f2fs_tune_ktype,
 				   NULL, "tuning");
 	if (ret)
-		goto put_kobject;
+		goto put_feat;
 
 	f2fs_proc_root = proc_mkdir("fs/f2fs", NULL);
 	if (!f2fs_proc_root) {
 		ret = -ENOMEM;
-		goto put_kobject;
+		goto put_tune;
 	}
 
 	return 0;
 
-put_kobject:
+put_tune:
 	kobject_put(&f2fs_tune);
+put_feat:
 	kobject_put(&f2fs_feat);
+unregister_kset:
 	kset_unregister(&f2fs_kset);
 	return ret;
 }