ipv6: fix the use of pcpu_tstats in ip6_tunnel

commit abb6013cca147ad940b0e9fee260d2d9e93b7018 upstream.

when read/write the 64bit data, the correct lock should be hold.

Fixes: 87b6d218f3adb ("tunnel: implement 64 bits statistics")

Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index 61a89951e7fed27bd0d192c818a78b934fad74b4..efc77acbe9e193d4730ec99fc66ea38c4f247607 100644 (file)
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -103,16 +103,25 @@ struct ip6_tnl_net {
 
 static struct net_device_stats *ip6_get_stats(struct net_device *dev)
 {
-       struct pcpu_tstats sum = { 0 };
+       struct pcpu_tstats tmp, sum = { 0 };
        int i;
 
        for_each_possible_cpu(i) {
+               unsigned int start;
                const struct pcpu_tstats *tstats = per_cpu_ptr(dev->tstats, i);
 
-               sum.rx_packets += tstats->rx_packets;
-               sum.rx_bytes   += tstats->rx_bytes;
-               sum.tx_packets += tstats->tx_packets;
-               sum.tx_bytes   += tstats->tx_bytes;
+               do {
+                       start = u64_stats_fetch_begin_bh(&tstats->syncp);
+                       tmp.rx_packets = tstats->rx_packets;
+                       tmp.rx_bytes = tstats->rx_bytes;
+                       tmp.tx_packets = tstats->tx_packets;
+                       tmp.tx_bytes =  tstats->tx_bytes;
+               } while (u64_stats_fetch_retry_bh(&tstats->syncp, start));
+
+               sum.rx_packets += tmp.rx_packets;
+               sum.rx_bytes   += tmp.rx_bytes;
+               sum.tx_packets += tmp.tx_packets;
+               sum.tx_bytes   += tmp.tx_bytes;
        }
        dev->stats.rx_packets = sum.rx_packets;
        dev->stats.rx_bytes   = sum.rx_bytes;
@@ -832,8 +841,10 @@ static int ip6_tnl_rcv(struct sk_buff *skb, __u16 protocol,
                }
 
                tstats = this_cpu_ptr(t->dev->tstats);
+               u64_stats_update_begin(&tstats->syncp);
                tstats->rx_packets++;
                tstats->rx_bytes += skb->len;
+               u64_stats_update_end(&tstats->syncp);
 
                netif_rx(skb);