Re: [PATCH net] can: j1939: j1939_sk_bind(): return failure if netdev is down
From: Oleksij Rempel <o.rempel@pengutronix.de>
Date: 2020-09-11 06:51:07
Also in:
linux-can, lkml
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 <redacted>Acked-by: Oleksij Rempel <o.rempel@pengutronix.de> Thank you!
quoted hunk ↗ jump to hunk
--- 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
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