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xen/netback: don't queue unlimited number of packages
commitbe81992f90
upstream. In case a guest isn't consuming incoming network traffic as fast as it is coming in, xen-netback is buffering network packages in unlimited numbers today. This can result in host OOM situations. Commitf48da8b14d
("xen-netback: fix unlimited guest Rx internal queue and carrier flapping") meant to introduce a mechanism to limit the amount of buffered data by stopping the Tx queue when reaching the data limit, but this doesn't work for cases like UDP. When hitting the limit don't queue further SKBs, but drop them instead. In order to be able to tell Rx packages have been dropped increment the rx_dropped statistics counter in this case. It should be noted that the old solution to continue queueing SKBs had the additional problem of an overflow of the 32-bit rx_queue_len value would result in intermittent Tx queue enabling. This is part of XSA-392 Fixes:f48da8b14d
("xen-netback: fix unlimited guest Rx internal queue and carrier flapping") Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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parent
8bfcd03852
commit
0d99b3c6bd
1 changed files with 11 additions and 7 deletions
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@ -88,16 +88,19 @@ void xenvif_rx_queue_tail(struct xenvif_queue *queue, struct sk_buff *skb)
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spin_lock_irqsave(&queue->rx_queue.lock, flags);
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if (skb_queue_empty(&queue->rx_queue))
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xenvif_update_needed_slots(queue, skb);
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__skb_queue_tail(&queue->rx_queue, skb);
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queue->rx_queue_len += skb->len;
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if (queue->rx_queue_len > queue->rx_queue_max) {
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if (queue->rx_queue_len >= queue->rx_queue_max) {
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struct net_device *dev = queue->vif->dev;
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netif_tx_stop_queue(netdev_get_tx_queue(dev, queue->id));
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kfree_skb(skb);
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queue->vif->dev->stats.rx_dropped++;
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} else {
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if (skb_queue_empty(&queue->rx_queue))
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xenvif_update_needed_slots(queue, skb);
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__skb_queue_tail(&queue->rx_queue, skb);
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queue->rx_queue_len += skb->len;
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}
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spin_unlock_irqrestore(&queue->rx_queue.lock, flags);
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@ -147,6 +150,7 @@ static void xenvif_rx_queue_drop_expired(struct xenvif_queue *queue)
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break;
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xenvif_rx_dequeue(queue);
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kfree_skb(skb);
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queue->vif->dev->stats.rx_dropped++;
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}
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}
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