From 681daee2443291419c57cccb0671f5f94a839005 Mon Sep 17 00:00:00 2001 From: Jason Wang Date: Wed, 26 Mar 2014 13:03:00 +0800 Subject: [PATCH] virtio-net: correct error handling of virtqueue_kick() Current error handling of virtqueue_kick() was wrong in two places: - The skb were freed immediately when virtqueue_kick() fail during xmit. This may lead double free since the skb was not detached from the virtqueue. - try_fill_recv() returns false when virtqueue_kick() fail. This will lead unnecessary rescheduling of refill work. Actually, it's safe to just ignore the kick failure in those two places. So this patch fixes this by partially revert commit 67975901183799af8e93ec60e322f9e2a1940b9b. Fixes 67975901183799af8e93ec60e322f9e2a1940b9b (virtio_net: verify if virtqueue_kick() succeeded). Cc: Heinz Graalfs Cc: Rusty Russell Cc: Michael S. Tsirkin Signed-off-by: Jason Wang Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller --- drivers/net/virtio_net.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index 5632a99cbbd2..841b60831df1 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -671,8 +671,7 @@ static bool try_fill_recv(struct receive_queue *rq, gfp_t gfp) if (err) break; } while (rq->vq->num_free); - if (unlikely(!virtqueue_kick(rq->vq))) - return false; + virtqueue_kick(rq->vq); return !oom; } @@ -877,7 +876,7 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) err = xmit_skb(sq, skb); /* This should not happen! */ - if (unlikely(err) || unlikely(!virtqueue_kick(sq->vq))) { + if (unlikely(err)) { dev->stats.tx_fifo_errors++; if (net_ratelimit()) dev_warn(&dev->dev, @@ -886,6 +885,7 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev) kfree_skb(skb); return NETDEV_TX_OK; } + virtqueue_kick(sq->vq); /* Don't wait up for transmitted skbs to be freed. */ skb_orphan(skb); -- 2.34.1