| From 22c696fed25c63c7f67508309820358b94a96b6d Mon Sep 17 00:00:00 2001 |
| From: Oleksij Rempel <linux@rempel-privat.de> |
| Date: Thu, 17 Jun 2021 15:06:23 +0200 |
| Subject: can: j1939: j1939_sk_init(): set SOCK_RCU_FREE to call sk_destruct() after RCU is done |
| |
| From: Oleksij Rempel <o.rempel@pengutronix.de> |
| |
| commit 22c696fed25c63c7f67508309820358b94a96b6d upstream. |
| |
| Set SOCK_RCU_FREE to let RCU to call sk_destruct() on completion. |
| Without this patch, we will run in to j1939_can_recv() after priv was |
| freed by j1939_sk_release()->j1939_sk_sock_destruct() |
| |
| Fixes: 25fe97cb7620 ("can: j1939: move j1939_priv_put() into sk_destruct callback") |
| Link: https://lore.kernel.org/r/20210617130623.12705-1-o.rempel@pengutronix.de |
| Cc: linux-stable <stable@vger.kernel.org> |
| Reported-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> |
| Reported-by: syzbot+bdf710cfc41c186fdff3@syzkaller.appspotmail.com |
| Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de> |
| Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| net/can/j1939/main.c | 4 ++++ |
| net/can/j1939/socket.c | 3 +++ |
| 2 files changed, 7 insertions(+) |
| |
| --- a/net/can/j1939/main.c |
| +++ b/net/can/j1939/main.c |
| @@ -193,6 +193,10 @@ static void j1939_can_rx_unregister(stru |
| can_rx_unregister(dev_net(ndev), ndev, J1939_CAN_ID, J1939_CAN_MASK, |
| j1939_can_recv, priv); |
| |
| + /* The last reference of priv is dropped by the RCU deferred |
| + * j1939_sk_sock_destruct() of the last socket, so we can |
| + * safely drop this reference here. |
| + */ |
| j1939_priv_put(priv); |
| } |
| |
| --- a/net/can/j1939/socket.c |
| +++ b/net/can/j1939/socket.c |
| @@ -398,6 +398,9 @@ static int j1939_sk_init(struct sock *sk |
| atomic_set(&jsk->skb_pending, 0); |
| spin_lock_init(&jsk->sk_session_queue_lock); |
| INIT_LIST_HEAD(&jsk->sk_session_queue); |
| + |
| + /* j1939_sk_sock_destruct() depends on SOCK_RCU_FREE flag */ |
| + sock_set_flag(sk, SOCK_RCU_FREE); |
| sk->sk_destruct = j1939_sk_sock_destruct; |
| sk->sk_protocol = CAN_J1939; |
| |