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

ipv6: avoid dad-failures for addresses with NODAD

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: ipv6-avoid-dad-failures-for-addresses-with-nodad.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 Mon Apr 9 17:09:24 CEST 2018

From: Mahesh Bandewar maheshb@google.com Date: Fri, 12 May 2017 17:03:39 -0700 Subject: ipv6: avoid dad-failures for addresses with NODAD

From: Mahesh Bandewar maheshb@google.com

[ Upstream commit 66eb9f86e50547ec2a8ff7a75997066a74ef584b ]

Every address gets added with TENTATIVE flag even for the addresses with IFA_F_NODAD flag and dad-work is scheduled for them. During this DAD process we realize it's an address with NODAD and complete the process without sending any probe. However the TENTATIVE flags stays on the address for sometime enough to cause misinterpretation when we receive a NS. While processing NS, if the address has TENTATIVE flag, we mark it DADFAILED and endup with an address that was originally configured as NODAD with DADFAILED.

We can't avoid scheduling dad_work for addresses with NODAD but we can avoid adding TENTATIVE flag to avoid this racy situation.

Signed-off-by: Mahesh Bandewar maheshb@google.com Acked-by: David Ahern dsahern@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/addrconf.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -988,7 +988,10 @@ ipv6_add_addr(struct inet6_dev *idev, co INIT_HLIST_NODE(&ifa->addr_lst); ifa->scope = scope; ifa->prefix_len = pfxlen; - ifa->flags = flags | IFA_F_TENTATIVE; + ifa->flags = flags; + /* No need to add the TENTATIVE flag for addresses with NODAD */ + if (!(flags & IFA_F_NODAD)) + ifa->flags |= IFA_F_TENTATIVE; ifa->valid_lft = valid_lft; ifa->prefered_lft = prefered_lft; ifa->cstamp = ifa->tstamp = jiffies;

Patches currently in stable-queue which might be from maheshb@google.com are

queue-4.9/bonding-don-t-update-slave-link-until-ready-to-commit.patch queue-4.9/ipv6-avoid-dad-failures-for-addresses-with-nodad.patch