diff mbox

[net] net: prevent sign extension in dev_get_stats()

Message ID 1498572140.736.115.camel@edumazet-glaptop3.roam.corp.google.com
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Eric Dumazet June 27, 2017, 2:02 p.m. UTC 
From: Eric Dumazet <edumazet@google.com>

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>
---
Note: I will provide similar other fixes in networking tree.

 net/core/dev.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

David Miller June 27, 2017, 6:51 p.m. UTC | #1 
From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Tue, 27 Jun 2017 07:02:20 -0700

> From: Eric Dumazet <edumazet@google.com>
> 
> 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>

Applied and queued up for -stable, thanks.
diff mbox

Patch

diff --git a/net/core/dev.c b/net/core/dev.c
index 7243421c9783..91bb55070533 100644
--- 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);