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

[David Miller]

From: Eric Dumazet 
Date: Tue, 27 Jun 2017 07:02:20 -0700

> From: Eric Dumazet 
> 
> 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 
> Cc: Jarod Wilson 

Applied and queued up for -stable, thanks.

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

[Eric Dumazet]

From: Eric Dumazet 

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 
Cc: Jarod Wilson 
---
Note: I will provide similar other fixes in networking tree.

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

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, >stats);
}
-   storage->rx_dropped += atomic_long_read(>rx_dropped);
-   storage->tx_dropped += atomic_long_read(>tx_dropped);
-   storage->rx_nohandler += atomic_long_read(>rx_nohandler);
+   storage->rx_dropped += (unsigned 
long)atomic_long_read(>rx_dropped);
+   storage->tx_dropped += (unsigned 
long)atomic_long_read(>tx_dropped);
+   storage->rx_nohandler += (unsigned 
long)atomic_long_read(>rx_nohandler);
return storage;
 }
 EXPORT_SYMBOL(dev_get_stats);