From: Zhang Changzhong zhangchangzhong@huawei.com
[ Upstream commit 08c487d8d807535f509ed80c6a10ad90e6872139 ]
When a netdev down event occurs after a successful call to j1939_sk_bind(), j1939_netdev_notify() can handle it correctly.
But if the netdev already in down state before calling j1939_sk_bind(), j1939_sk_release() will stay in wait_event_interruptible() blocked forever. Because in this case, j1939_netdev_notify() won't be called and j1939_tp_txtimer() won't call j1939_session_cancel() or other function to clear session for ENETDOWN error, this lead to mismatch of j1939_session_get/put() and jsk->skb_pending will never decrease to zero.
To reproduce it use following commands: 1. ip link add dev vcan0 type vcan 2. j1939acd -r 100,80-120 1122334455667788 vcan0 3. presses ctrl-c and thread will be blocked forever
This patch adds check for ndev->flags in j1939_sk_bind() to avoid this kind of situation and return with -ENETDOWN.
Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Signed-off-by: Zhang Changzhong zhangchangzhong@huawei.com Link: https://lore.kernel.org/r/1599460308-18770-1-git-send-email-zhangchangzhong@... Acked-by: Oleksij Rempel o.rempel@pengutronix.de Signed-off-by: Marc Kleine-Budde mkl@pengutronix.de Signed-off-by: Sasha Levin sashal@kernel.org --- net/can/j1939/socket.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c index 1be4c898b2fa8..f23966526a885 100644 --- a/net/can/j1939/socket.c +++ b/net/can/j1939/socket.c @@ -475,6 +475,12 @@ static int j1939_sk_bind(struct socket *sock, struct sockaddr *uaddr, int len) goto out_release_sock; }
+ if (!(ndev->flags & IFF_UP)) { + dev_put(ndev); + ret = -ENETDOWN; + goto out_release_sock; + } + priv = j1939_netdev_start(ndev); dev_put(ndev); if (IS_ERR(priv)) {