4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Mahesh Bandewar <mahe...@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 <mahe...@google.com> Acked-by: David Ahern <dsah...@gmail.com> Signed-off-by: David S. Miller <da...@davemloft.net> Signed-off-by: Sasha Levin <alexander.le...@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gre...@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;