This is a note to let you know that I've just added the patch titled

ip6_gre: init dev->mtu and dev->hard_header_len correctly

to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: ip6_gre-init-dev-mtu-and-dev-hard_header_len-correctly.patch and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Sun Jan 28 17:37:09 CET 2018

From: Alexey Kodanev alexey.kodanev@oracle.com Date: Thu, 18 Jan 2018 20:51:12 +0300 Subject: ip6_gre: init dev->mtu and dev->hard_header_len correctly

From: Alexey Kodanev alexey.kodanev@oracle.com

[ Upstream commit 128bb975dc3c25d00de04e503e2fe0a780d04459 ]

Commit b05229f44228 ("gre6: Cleanup GREv6 transmit path, call common GRE functions") moved dev->mtu initialization from ip6gre_tunnel_setup() to ip6gre_tunnel_init(), as a result, the previously set values, before ndo_init(), are reset in the following cases:

* rtnl_create_link() can update dev->mtu from IFLA_MTU parameter.

* ip6gre_tnl_link_config() is invoked before ndo_init() in netlink and ioctl setup, so ndo_init() can reset MTU adjustments with the lower device MTU as well, dev->mtu and dev->hard_header_len.

Not applicable for ip6gretap because it has one more call to ip6gre_tnl_link_config(tunnel, 1) in ip6gre_tap_init().

Fix the first case by updating dev->mtu with 'tb[IFLA_MTU]' parameter if a user sets it manually on a device creation, and fix the second one by moving ip6gre_tnl_link_config() call after register_netdevice().

Fixes: b05229f44228 ("gre6: Cleanup GREv6 transmit path, call common GRE functions") Fixes: db2ec95d1ba4 ("ip6_gre: Fix MTU setting") Signed-off-by: Alexey Kodanev alexey.kodanev@oracle.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/ip6_gre.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)

--- a/net/ipv6/ip6_gre.c +++ b/net/ipv6/ip6_gre.c @@ -337,11 +337,12 @@ static struct ip6_tnl *ip6gre_tunnel_loc

nt->dev = dev; nt->net = dev_net(dev); - ip6gre_tnl_link_config(nt, 1);

if (register_netdevice(dev) < 0) goto failed_free;

+ ip6gre_tnl_link_config(nt, 1); + /* Can use a lockless transmit, unless we generate output sequences */ if (!(nt->parms.o_flags & TUNNEL_SEQ)) dev->features |= NETIF_F_LLTX; @@ -1263,7 +1264,6 @@ static void ip6gre_netlink_parms(struct

static int ip6gre_tap_init(struct net_device *dev) { - struct ip6_tnl *tunnel; int ret;

ret = ip6gre_tunnel_init_common(dev); @@ -1272,10 +1272,6 @@ static int ip6gre_tap_init(struct net_de

dev->priv_flags |= IFF_LIVE_ADDR_CHANGE;

- tunnel = netdev_priv(dev); - - ip6gre_tnl_link_config(tunnel, 1); - return 0; }

@@ -1370,7 +1366,6 @@ static int ip6gre_newlink(struct net *sr

nt->dev = dev; nt->net = dev_net(dev); - ip6gre_tnl_link_config(nt, !tb[IFLA_MTU]);

dev->features |= GRE6_FEATURES; dev->hw_features |= GRE6_FEATURES; @@ -1396,6 +1391,11 @@ static int ip6gre_newlink(struct net *sr if (err) goto out;

+ ip6gre_tnl_link_config(nt, !tb[IFLA_MTU]); + + if (tb[IFLA_MTU]) + ip6_tnl_change_mtu(dev, nla_get_u32(tb[IFLA_MTU])); + dev_hold(dev); ip6gre_tunnel_link(ign, nt);

Patches currently in stable-queue which might be from alexey.kodanev@oracle.com are

queue-4.9/dccp-don-t-restart-ccid2_hc_tx_rto_expire-if-sk-in-closed-state.patch queue-4.9/ip6_gre-init-dev-mtu-and-dev-hard_header_len-correctly.patch