[linux-next] LinuxNextTracking branch, master, updated. next-20170131

batman at open-mesh.org batman at open-mesh.org
Wed Feb 1 00:15:52 CET 2017


The following commit has been merged in the master branch:
commit 7c946062b3ae2b7f002383e5e402113e98ad3c77
Author: Sven Eckelmann <sven at narfation.org>
Date:   Sat Jan 28 10:12:39 2017 +0100

    batman-adv: Fix double call of dev_queue_xmit
    
    The net_xmit_eval has side effects because it is not making sure that e
    isn't evaluated twice.
    
        #define net_xmit_eval(e)        ((e) == NET_XMIT_CN ? 0 : (e))
    
    The code requested by David Miller [1]
    
        return net_xmit_eval(dev_queue_xmit(skb));
    
    will get transformed into
    
        return ((dev_queue_xmit(skb)) == NET_XMIT_CN ? 0 : (dev_queue_xmit(skb)))
    
    dev_queue_xmit will therefore be tried again (with an already consumed skb)
    whenever the return code is not NET_XMIT_CN.
    
    [1] https://lkml.kernel.org/r/20170125.225624.965229145391320056.davem@davemloft.net
    
    Fixes: c33705188c49 ("batman-adv: Treat NET_XMIT_CN as transmit successfully")
    Signed-off-by: Sven Eckelmann <sven at narfation.org>
    Signed-off-by: Simon Wunderlich <sw at simonwunderlich.de>

diff --git a/net/batman-adv/send.c b/net/batman-adv/send.c
index d9b2889..1489ec2 100644
--- a/net/batman-adv/send.c
+++ b/net/batman-adv/send.c
@@ -77,6 +77,7 @@ int batadv_send_skb_packet(struct sk_buff *skb,
 {
 	struct batadv_priv *bat_priv;
 	struct ethhdr *ethhdr;
+	int ret;
 
 	bat_priv = netdev_priv(hard_iface->soft_iface);
 
@@ -115,7 +116,8 @@ int batadv_send_skb_packet(struct sk_buff *skb,
 	 * congestion and traffic shaping, it drops and returns NET_XMIT_DROP
 	 * (which is > 0). This will not be treated as an error.
 	 */
-	return net_xmit_eval(dev_queue_xmit(skb));
+	ret = dev_queue_xmit(skb);
+	return net_xmit_eval(ret);
 send_skb_err:
 	kfree_skb(skb);
 	return NET_XMIT_DROP;

-- 
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