virtio_net: avoid data-races on dev->stats fields

[ Upstream commit d12a26b74fb77434b73fe39022266c4b00907219 ]

Use DEV_STATS_INC() and DEV_STATS_READ() which provide
atomicity on paths that can be used concurrently.

Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Stable-dep-of: 2311e06b9bf3 ("virtio_net: fix missing dma unmap for resize")
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index 0c0be6b..c1c6347 100644 (file)
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1258,7 +1258,7 @@ static struct sk_buff *receive_small(struct net_device *dev,
        if (unlikely(len > GOOD_PACKET_LEN)) {
                pr_debug("%s: rx error: len %u exceeds max size %d\n",
                         dev->name, len, GOOD_PACKET_LEN);
-               dev->stats.rx_length_errors++;
+               DEV_STATS_INC(dev, rx_length_errors);
                goto err;
        }
 
@@ -1323,7 +1323,7 @@ static void mergeable_buf_free(struct receive_queue *rq, int num_buf,
                if (unlikely(!buf)) {
                        pr_debug("%s: rx error: %d buffers missing\n",
                                 dev->name, num_buf);
-                       dev->stats.rx_length_errors++;
+                       DEV_STATS_INC(dev, rx_length_errors);
                        break;
                }
                u64_stats_add(&stats->bytes, len);
@@ -1432,7 +1432,7 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
                        pr_debug("%s: rx error: %d buffers out of %d missing\n",
                                 dev->name, *num_buf,
                                 virtio16_to_cpu(vi->vdev, hdr->num_buffers));
-                       dev->stats.rx_length_errors++;
+                       DEV_STATS_INC(dev, rx_length_errors);
                        goto err;
                }
 
@@ -1451,7 +1451,7 @@ static int virtnet_build_xdp_buff_mrg(struct net_device *dev,
                        put_page(page);
                        pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
                                 dev->name, len, (unsigned long)(truesize - room));
-                       dev->stats.rx_length_errors++;
+                       DEV_STATS_INC(dev, rx_length_errors);
                        goto err;
                }
 
@@ -1630,7 +1630,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
        if (unlikely(len > truesize - room)) {
                pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
                         dev->name, len, (unsigned long)(truesize - room));
-               dev->stats.rx_length_errors++;
+               DEV_STATS_INC(dev, rx_length_errors);
                goto err_skb;
        }
 
@@ -1662,7 +1662,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
                                 dev->name, num_buf,
                                 virtio16_to_cpu(vi->vdev,
                                                 hdr->num_buffers));
-                       dev->stats.rx_length_errors++;
+                       DEV_STATS_INC(dev, rx_length_errors);
                        goto err_buf;
                }
 
@@ -1676,7 +1676,7 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
                if (unlikely(len > truesize - room)) {
                        pr_debug("%s: rx error: len %u exceeds truesize %lu\n",
                                 dev->name, len, (unsigned long)(truesize - room));
-                       dev->stats.rx_length_errors++;
+                       DEV_STATS_INC(dev, rx_length_errors);
                        goto err_skb;
                }
 
@@ -1763,7 +1763,7 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
 
        if (unlikely(len < vi->hdr_len + ETH_HLEN)) {
                pr_debug("%s: short packet %i\n", dev->name, len);
-               dev->stats.rx_length_errors++;
+               DEV_STATS_INC(dev, rx_length_errors);
                virtnet_rq_free_unused_buf(rq->vq, buf);
                return;
        }
@@ -1803,7 +1803,7 @@ static void receive_buf(struct virtnet_info *vi, struct receive_queue *rq,
        return;
 
 frame_err:
-       dev->stats.rx_frame_errors++;
+       DEV_STATS_INC(dev, rx_frame_errors);
        dev_kfree_skb(skb);
 }
 
@@ -2352,12 +2352,12 @@ static netdev_tx_t start_xmit(struct sk_buff *skb, struct net_device *dev)
 
        /* This should not happen! */
        if (unlikely(err)) {
-               dev->stats.tx_fifo_errors++;
+               DEV_STATS_INC(dev, tx_fifo_errors);
                if (net_ratelimit())
                        dev_warn(&dev->dev,
                                 "Unexpected TXQ (%d) queue failure: %d\n",
                                 qnum, err);
-               dev->stats.tx_dropped++;
+               DEV_STATS_INC(dev, tx_dropped);
                dev_kfree_skb_any(skb);
                return NETDEV_TX_OK;
        }
@@ -2576,10 +2576,10 @@ static void virtnet_stats(struct net_device *dev,
                tot->tx_errors  += terrors;
        }
 
-       tot->tx_dropped = dev->stats.tx_dropped;
-       tot->tx_fifo_errors = dev->stats.tx_fifo_errors;
-       tot->rx_length_errors = dev->stats.rx_length_errors;
-       tot->rx_frame_errors = dev->stats.rx_frame_errors;
+       tot->tx_dropped = DEV_STATS_READ(dev, tx_dropped);
+       tot->tx_fifo_errors = DEV_STATS_READ(dev, tx_fifo_errors);
+       tot->rx_length_errors = DEV_STATS_READ(dev, rx_length_errors);
+       tot->rx_frame_errors = DEV_STATS_READ(dev, rx_frame_errors);
 }
 
 static void virtnet_ack_link_announce(struct virtnet_info *vi)