Re: [syzbot] kernel BUG in create_default_group...

[Edward Adam Davis <eadavis@sina.com>]

From: Edward Aadm Davis <eadavis@sina.com>

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git 58161ead29e5

diff --git a/fs/configfs/dir.c b/fs/configfs/dir.c
index eda80c2a2d38..45a955b8ab36 100644
--- a/fs/configfs/dir.c
+++ b/fs/configfs/dir.c
@@ -313,7 +313,6 @@ static int configfs_create_dir(struct config_item *item, struct dentry *dentry,
 		goto out_remove;
 
 	inode->i_op = &configfs_dir_inode_operations;
-	inode->i_fop = &configfs_dir_operations;
 	/* directory inodes start off with i_nlink == 2 (for "." entry) */
 	inc_nlink(inode);
 	d_make_persistent(dentry, inode);
@@ -930,6 +929,10 @@ static int configfs_attach_group(struct config_item *item,
 		inode_unlock(d_inode(dentry));
 		if (ret)
 			d_delete(dentry);
+		else {
+			struct inode *inode = d_inode(dentry);
+			inode->i_fop = &configfs_dir_operations;
+		}
 	}
 
 	return ret;
@@ -1430,8 +1433,13 @@ static struct dentry *configfs_mkdir(struct mnt_idmap *idmap, struct inode *dir,
 
 	if (group)
 		ret = configfs_attach_group(item, dentry, frag);
-	else
+	else {
 		ret = configfs_attach_item(item, dentry, frag);
+		if (!ret) {
+			struct inode *inode = d_inode(dentry);
+			inode->i_fop = &configfs_dir_operations;
+		}
+	}
 
 	spin_lock(&configfs_dirent_lock);
 	sd->s_type &= ~CONFIGFS_USET_IN_MKDIR;