tg3: Fix race condition in tg3_get_stats64()

Spinlock should be taken before checking for tp->hw_stats.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index 50045ed1e8c0..f03614be9fd5 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -12524,10 +12524,12 @@ static struct rtnl_link_stats64 *tg3_get_stats64(struct net_device *dev,
 {
         struct tg3 *tp = netdev_priv(dev);
 
-        if (!tp->hw_stats)
+        spin_lock_bh(&tp->lock);
+        if (!tp->hw_stats) {
+                spin_unlock_bh(&tp->lock);
                 return &tp->net_stats_prev;
+        }
 
-        spin_lock_bh(&tp->lock);
         tg3_get_nstats(tp, stats);
         spin_unlock_bh(&tp->lock);