[PATCH 3.13.y-ckt 010/143] bridge: dont send notification when skb->len == 0 in rtnl_bridge_notify

Kamal Mostafa kamal at canonical.com
Tue Mar 31 19:46:15 UTC 2015

3.13.11-ckt18 -stable review patch.  If anyone has any objections, please let me know.


From: Roopa Prabhu <roopa at cumulusnetworks.com>

[ Upstream commit 59ccaaaa49b5b096cdc1f16706a9f931416b2332 ]

Reported in: https://bugzilla.kernel.org/show_bug.cgi?id=92081

This patch avoids calling rtnl_notify if the device ndo_bridge_getlink
handler does not return any bytes in the skb.

Alternately, the skb->len check can be moved inside rtnl_notify.

For the bridge vlan case described in 92081, there is also a fix needed
in bridge driver to generate a proper notification. Will fix that in
subsequent patch.

v2: rebase patch on net tree

Signed-off-by: Roopa Prabhu <roopa at cumulusnetworks.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
 net/core/rtnetlink.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 7dca4b4..f48db99 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2542,12 +2542,16 @@ static int rtnl_bridge_notify(struct net_device *dev, u16 flags)
 			goto errout;
+	if (!skb->len)
+		goto errout;
 	rtnl_notify(skb, net, 0, RTNLGRP_LINK, NULL, GFP_ATOMIC);
 	return 0;
 	WARN_ON(err == -EMSGSIZE);
-	rtnl_set_sk_err(net, RTNLGRP_LINK, err);
+	if (err)
+		rtnl_set_sk_err(net, RTNLGRP_LINK, err);
 	return err;

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