| Message ID | 1599460308-18770-1-git-send-email-zhangchangzhong@huawei.com |
|---|---|
| State | Awaiting Upstream |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net] can: j1939: j1939_sk_bind(): return failure if netdev is down | expand |
On Mon, Sep 07, 2020 at 02:31:48PM +0800, Zhang Changzhong wrote: > 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> Acked-by: Oleksij Rempel <o.rempel@pengutronix.de> Thank you! > --- > 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 1be4c89..f239665 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)) { > -- > 2.9.5 > >
diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c index 1be4c89..f239665 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)) {
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> --- net/can/j1939/socket.c | 6 ++++++ 1 file changed, 6 insertions(+)