net: prevent sign extension in dev_get_stats()

Similar to the fix provided by Dominik Heidler in commit
9b3dc0a17d73 ("l2tp: cast l2tp traffic counter to unsigned")
we need to take care of 32bit kernels in dev_get_stats().

When using atomic_long_read(), we add a 'long' to u64 and
might misinterpret high order bit, unless we cast to unsigned.

Fixes: caf586e5f23ce ("net: add a core netdev->rx_dropped counter")
Fixes: 015f0688f57ca ("net: net: add a core netdev->tx_dropped counter")
Fixes: 6e7333d315a76 ("net: add rx_nohandler stat counter")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jarod Wilson <jarod@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/dev.c b/net/core/dev.c
index 7243421c9783bf060dac1938fc1f2f59a4afafea..91bb5507053309c345f1f0cf99c4a09cba013f96 100644 (file)
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -7783,9 +7783,9 @@ struct rtnl_link_stats64 *dev_get_stats(struct net_device *dev,
        } else {
                netdev_stats_to_stats64(storage, &dev->stats);
        }
-       storage->rx_dropped += atomic_long_read(&dev->rx_dropped);
-       storage->tx_dropped += atomic_long_read(&dev->tx_dropped);
-       storage->rx_nohandler += atomic_long_read(&dev->rx_nohandler);
+       storage->rx_dropped += (unsigned long)atomic_long_read(&dev->rx_dropped);
+       storage->tx_dropped += (unsigned long)atomic_long_read(&dev->tx_dropped);
+       storage->rx_nohandler += (unsigned long)atomic_long_read(&dev->rx_nohandler);
        return storage;
 }
 EXPORT_SYMBOL(dev_get_stats);