From: Fedor Pchelkin pchelkin@ispras.ru

commit 8ef49f7f8244424adcf4a546dba4cbbeb0b09c09 upstream.

We should warn user-space that it is doing something wrong when trying to activate sessions with identical parameters but WARN_ON_ONCE macro can not be used here as it serves a different purpose.

So it would be good to replace it with netdev_warn_once() message.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: 9d71dd0 ("can: add support of SAE J1939 protocol") Signed-off-by: Fedor Pchelkin pchelkin@ispras.ru Signed-off-by: Alexey Khoroshilov khoroshilov@ispras.ru Acked-by: Oleksij Rempel o.rempel@pengutronix.de Link: https://lore.kernel.org/all/20220729143655.1108297-1-pchelkin@ispras.ru [mkl: fix indention] Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de --- net/can/j1939/socket.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c index e1a399821238..709141abd131 100644 --- a/net/can/j1939/socket.c +++ b/net/can/j1939/socket.c @@ -178,7 +178,10 @@ static void j1939_sk_queue_activate_next_locked(struct j1939_session *session) if (!first) return;

- if (WARN_ON_ONCE(j1939_session_activate(first))) { + if (j1939_session_activate(first)) { + netdev_warn_once(first->priv->ndev, + "%s: 0x%p: Identical session is already activated.\n", + __func__, first); first->err = -EBUSY; goto activate_next; } else {