From 5ef9f289c4e698054e5687edb54f0da3cdc9173a Mon Sep 17 00:00:00 2001 From: Ian Wienand Date: Wed, 3 Aug 2016 15:44:57 +1000 Subject: OVS: Ignore negative headroom value net_device->ndo_set_rx_headroom (introduced in 871b642adebe300be2e50aa5f65a418510f636ec) says "Setting a negtaive value reset the rx headroom to the default value". It seems that the OVS implementation in 3a927bc7cf9d0fbe8f4a8189dd5f8440228f64e7 overlooked this and sets dev->needed_headroom unconditionally. This doesn't have an immediate effect, but can mess up later LL_RESERVED_SPACE calculations, such as done in net/ipv6/mcast.c:mld_newpack. For reference, this issue was found from a skb_panic raised there after the length calculations had given the wrong result. Note the other current users of this interface (drivers/net/tun.c:tun_set_headroom and drivers/net/veth.c:veth_set_rx_headroom) are both checking this correctly thus need no modification. Thanks to Ben for some pointers from the crash dumps! Cc: Benjamin Poirier Cc: Paolo Abeni Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1361414 Signed-off-by: Ian Wienand Signed-off-by: David S. Miller --- net/openvswitch/vport-internal_dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/openvswitch/vport-internal_dev.c b/net/openvswitch/vport-internal_dev.c index 434e04c3a189..95c36147a6e1 100644 --- a/net/openvswitch/vport-internal_dev.c +++ b/net/openvswitch/vport-internal_dev.c @@ -140,7 +140,7 @@ internal_get_stats(struct net_device *dev, struct rtnl_link_stats64 *stats) static void internal_set_rx_headroom(struct net_device *dev, int new_hr) { - dev->needed_headroom = new_hr; + dev->needed_headroom = new_hr < 0 ? 0 : new_hr; } static const struct net_device_ops internal_dev_netdev_ops = { -- cgit v1.2.3-59-g8ed1b