xen-netback: fix race condition on XenBus disconnect (b17075d5) · Commits · 戴 / test

drivers/net/xen-netback/interface.c

+17 −9

Original line number	Diff line number	Diff line
		@@ -165,13 +165,17 @@ static int xenvif_start_xmit(struct sk_buff skb, struct net_device dev)
		{
		struct xenvif *vif = netdev_priv(dev);
		struct xenvif_queue *queue = NULL;
		unsigned int num_queues = vif->num_queues;
		unsigned int num_queues;
		u16 index;
		struct xenvif_rx_cb *cb;

		BUG_ON(skb->dev != dev);

		/* Drop the packet if queues are not set up */
		/* Drop the packet if queues are not set up.
		* This handler should be called inside an RCU read section
		* so we don't need to enter it here explicitly.
		*/
		num_queues = READ_ONCE(vif->num_queues);
		if (num_queues < 1)
		goto drop;

		@@ -222,18 +226,18 @@ static struct net_device_stats xenvif_get_stats(struct net_device dev)
		{
		struct xenvif *vif = netdev_priv(dev);
		struct xenvif_queue *queue = NULL;
		unsigned int num_queues;
		u64 rx_bytes = 0;
		u64 rx_packets = 0;
		u64 tx_bytes = 0;
		u64 tx_packets = 0;
		unsigned int index;

		spin_lock(&vif->lock);
		if (vif->queues == NULL)
		goto out;
		rcu_read_lock();
		num_queues = READ_ONCE(vif->num_queues);

		/* Aggregate tx and rx stats from each queue */
		for (index = 0; index < vif->num_queues; ++index) {
		for (index = 0; index < num_queues; ++index) {
		queue = &vif->queues[index];
		rx_bytes += queue->stats.rx_bytes;
		rx_packets += queue->stats.rx_packets;
		@@ -241,8 +245,7 @@ static struct net_device_stats xenvif_get_stats(struct net_device dev)
		tx_packets += queue->stats.tx_packets;
		}

		out:
		spin_unlock(&vif->lock);
		rcu_read_unlock();

		vif->dev->stats.rx_bytes = rx_bytes;
		vif->dev->stats.rx_packets = rx_packets;
		@@ -378,10 +381,13 @@ static void xenvif_get_ethtool_stats(struct net_device *dev,
		struct ethtool_stats stats, u64 data)
		{
		struct xenvif *vif = netdev_priv(dev);
		unsigned int num_queues = vif->num_queues;
		unsigned int num_queues;
		int i;
		unsigned int queue_index;

		rcu_read_lock();
		num_queues = READ_ONCE(vif->num_queues);

		for (i = 0; i < ARRAY_SIZE(xenvif_stats); i++) {
		unsigned long accum = 0;
		for (queue_index = 0; queue_index < num_queues; ++queue_index) {
		@@ -390,6 +396,8 @@ static void xenvif_get_ethtool_stats(struct net_device *dev,
		}
		data[i] = accum;
		}

		rcu_read_unlock();
		}

		static void xenvif_get_strings(struct net_device dev, u32 stringset, u8 data)

drivers/net/xen-netback/netback.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -214,7 +214,7 @@ static void xenvif_fatal_tx_err(struct xenvif *vif)
		netdev_err(vif->dev, "fatal error; disabling device\n");
		vif->disabled = true;
		/* Disable the vif from queue 0's kthread */
		if (vif->queues)
		if (vif->num_queues)
		xenvif_kick_thread(&vif->queues[0]);
		}

drivers/net/xen-netback/xenbus.c

+10 −10

Original line number	Diff line number	Diff line
		@@ -495,26 +495,26 @@ static void backend_disconnect(struct backend_info *be)
		struct xenvif *vif = be->vif;

		if (vif) {
		unsigned int num_queues = vif->num_queues;
		unsigned int queue_index;
		struct xenvif_queue *queues;

		xen_unregister_watchers(vif);
		#ifdef CONFIG_DEBUG_FS
		xenvif_debugfs_delif(vif);
		#endif /* CONFIG_DEBUG_FS */
		xenvif_disconnect_data(vif);
		for (queue_index = 0;
		queue_index < vif->num_queues;
		++queue_index)
		xenvif_deinit_queue(&vif->queues[queue_index]);

		spin_lock(&vif->lock);
		queues = vif->queues;
		/* At this point some of the handlers may still be active
		* so we need to have additional synchronization here.
		*/
		vif->num_queues = 0;
		vif->queues = NULL;
		spin_unlock(&vif->lock);
		synchronize_net();

		vfree(queues);
		for (queue_index = 0; queue_index < num_queues; ++queue_index)
		xenvif_deinit_queue(&vif->queues[queue_index]);

		vfree(vif->queues);
		vif->queues = NULL;

		xenvif_disconnect_ctrl(vif);
		}

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