The ea block expansion need to access s_root while it is already set as NULL when umount is triggered. Refuse this request to avoid panic. Reported-by: syzbot+2dacb8f015bf1420155f@xxxxxxxxxxxxxxxxxxxxxxxxx Link: https://syzkaller.appspot.com/bug?id=3613786cb88c93aa1c6a279b1df6a7b201347d08 Signed-off-by: Jun Nie <jun.nie@xxxxxxxxxx> --- fs/ext4/xattr.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c index 235a517d9c17..b350510b798c 100644 --- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -1422,6 +1422,13 @@ static struct inode *ext4_xattr_inode_create(handle_t *handle, uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) }; int err; + if (inode->i_sb->s_root == NULL) { + ext4_warning(inode->i_sb, + "refuse to create EA inode when umounting"); + WARN_ON(1); + return ERR_PTR(-EINVAL); + } + /* * Let the next inode be the goal, so we try and allocate the EA inode * in the same group, or nearby one. -- 2.34.1
