[ovs-dev] [PATCH 1/2] datapath: Don't free vport until all references are gone.

Jesse Gross jesse at nicira.com
Fri Feb 25 00:23:06 UTC 2011


We currently call vport_free() for internal devices after the
device is unregistered.  This takes care of callers that use
either RTNL or RCU but not ones that have only a device reference.
In particular, if stats are requested while a datapath is being
unregistered we can try to use the vport data structures which
have already been freed.

Bug #4736

Signed-off-by: Jesse Gross <jesse at nicira.com>
---
 datapath/vport-internal_dev.c |   13 ++++++++++---
 1 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/datapath/vport-internal_dev.c b/datapath/vport-internal_dev.c
index 0b91b34..63f3f69 100644
--- a/datapath/vport-internal_dev.c
+++ b/datapath/vport-internal_dev.c
@@ -132,6 +132,14 @@ static int internal_dev_do_ioctl(struct net_device *dev, struct ifreq *ifr, int
 	return -EOPNOTSUPP;
 }
 
+static void internal_dev_destructor(struct net_device *dev)
+{
+	struct vport *vport = internal_dev_get_vport(dev);
+
+	vport_free(vport);
+	free_netdev(dev);
+}
+
 #ifdef HAVE_NET_DEVICE_OPS
 static const struct net_device_ops internal_dev_netdev_ops = {
 	.ndo_open = internal_dev_open,
@@ -160,7 +168,7 @@ static void do_setup(struct net_device *netdev)
 	netdev->change_mtu = internal_dev_change_mtu;
 #endif
 
-	netdev->destructor = free_netdev;
+	netdev->destructor = internal_dev_destructor;
 	SET_ETHTOOL_OPS(netdev, &internal_dev_ethtool_ops);
 	netdev->tx_queue_len = 0;
 
@@ -219,9 +227,8 @@ static int internal_dev_destroy(struct vport *vport)
 	netif_stop_queue(netdev_vport->dev);
 	dev_set_promiscuity(netdev_vport->dev, -1);
 
-	unregister_netdevice(netdev_vport->dev);
 	/* unregister_netdevice() waits for an RCU grace period. */
-	vport_free(vport);
+	unregister_netdevice(netdev_vport->dev);
 
 	return 0;
 }
-- 
1.7.1





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