ipv6: fix the use of pcpu_tstats in ip6_tunnel

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>

1 files changed, 16 insertions, 5 deletions

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index d6062325db08..7881965a8248 100644
--- 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;
@@ -824,8 +833,10 @@ 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);