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authorBjorn Helgaas <bhelgaas@google.com>2016-03-24 21:56:21 -0500
committerDavid S. Miller <davem@davemloft.net>2016-03-25 11:23:14 -0400
commit543e3a8da5a4c453e992d5351ef405d5e32f27d7 (patch)
treebc8514faff2b7548705e02d57b711d7d96843abb /net/core/netpoll.c
parent7dd399130efb5a454daf24075b7563d197114e39 (diff)
netpoll: Fix extra refcount release in netpoll_cleanup()
netpoll_setup() does a dev_hold() on np->dev, the netpoll device. If it fails, it correctly does a dev_put() but leaves np->dev set. If we call netpoll_cleanup() after the failure, np->dev is still set so we do another dev_put(), which decrements the refcount an extra time. It's questionable to call netpoll_cleanup() after netpoll_setup() fails, but it can be difficult to find the problem, and we can easily avoid it in this case. The extra decrements can lead to hangs like this: unregister_netdevice: waiting for bond0 to become free. Usage count = -3 Set and clear np->dev at the points where we dev_hold() and dev_put() the device. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core/netpoll.c')
-rw-r--r--net/core/netpoll.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/core/netpoll.c b/net/core/netpoll.c
index 94acfc89ad97..a57bd17805b4 100644
--- a/net/core/netpoll.c
+++ b/net/core/netpoll.c
@@ -603,7 +603,6 @@ int __netpoll_setup(struct netpoll *np, struct net_device *ndev)
const struct net_device_ops *ops;
int err;
- np->dev = ndev;
strlcpy(np->dev_name, ndev->name, IFNAMSIZ);
INIT_WORK(&np->cleanup_work, netpoll_async_cleanup);
@@ -670,6 +669,7 @@ int netpoll_setup(struct netpoll *np)
goto unlock;
}
dev_hold(ndev);
+ np->dev = ndev;
if (netdev_master_upper_dev_get(ndev)) {
np_err(np, "%s is a slave device, aborting\n", np->dev_name);
@@ -770,6 +770,7 @@ int netpoll_setup(struct netpoll *np)
return 0;
put:
+ np->dev = NULL;
dev_put(ndev);
unlock:
rtnl_unlock();