4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Tom Herbert <tom@xxxxxxxxxxxxxx> commit dff8baa261174de689a44572d0ea182d7aa70598 upstream. In kcm_attach strp_done is called when sk_user_data is already set to fail the attach. strp_done needs the strp to be stopped and warns if it isn't. Call strp_stop in this case to eliminate the warning message. Reported-by: syzbot+88dfb55e4c8b770d86e3@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: e5571240236c5652f ("kcm: Check if sk_user_data already set in kcm_attach" Signed-off-by: Tom Herbert <tom@xxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/kcm/kcmsock.c | 1 + 1 file changed, 1 insertion(+) --- a/net/kcm/kcmsock.c +++ b/net/kcm/kcmsock.c @@ -1424,6 +1424,7 @@ static int kcm_attach(struct socket *soc */ if (csk->sk_user_data) { write_unlock_bh(&csk->sk_callback_lock); + strp_stop(&psock->strp); strp_done(&psock->strp); kmem_cache_free(kcm_psockp, psock); err = -EALREADY;