4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

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


[ Upstream commit 7be2c82cfd5d28d7adb66821a992604eb6dd112e ]

Ashizuka reported a highmem oddity and sent a patch for freescale
fec driver.

But the problem root cause is that core networking stack
must ensure no skb with highmem fragment is ever sent through
a device that does not assert NETIF_F_HIGHDMA in its features.

We need to call illegal_highdma() from harmonize_features()
regardless of CSUM checks.

Fixes: ec5f06156423 ("net: Kill link between CSUM and SG features.")
Signed-off-by: Eric Dumazet <eduma...@google.com>
Cc: Pravin Shelar <pshe...@ovn.org>
Reported-by: "Ashizuka, Yuusuke" <ashid...@jp.fujitsu.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 net/core/dev.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2650,9 +2650,9 @@ static netdev_features_t harmonize_featu
        if (skb->ip_summed != CHECKSUM_NONE &&
            !can_checksum_protocol(features, type)) {
                features &= ~NETIF_F_ALL_CSUM;
-       } else if (illegal_highdma(skb->dev, skb)) {
-               features &= ~NETIF_F_SG;
        }
+       if (illegal_highdma(skb->dev, skb))
+               features &= ~NETIF_F_SG;
 
        return features;
 }


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