From: Zhang Changzhong <zhangchangzhong@huawei.com>
To: <robin@protonic.nl>, <linux@rempel-privat.de>,
<kernel@pengutronix.de>, <socketcan@hartkopp.net>,
<mkl@pengutronix.de>, <davem@davemloft.net>, <kuba@kernel.org>
Cc: <linux-can@vger.kernel.org>, <netdev@vger.kernel.org>,
<linux-kernel@vger.kernel.org>
Subject: [PATCH net] can: j1939: j1939_sk_bind(): return failure if netdev is down
Date: Mon, 7 Sep 2020 14:31:48 +0800 [thread overview]
Message-ID: <1599460308-18770-1-git-send-email-zhangchangzhong@huawei.com> (raw)
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(+)
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
next reply other threads:[~2020-09-07 6:33 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-07 6:31 Zhang Changzhong [this message]
2020-09-11 6:50 ` [PATCH net] can: j1939: j1939_sk_bind(): return failure if netdev is down Oleksij Rempel
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