[SRU][X, Z, A, B][PATCH 0/1] ipv6: Do not consider linkdown nexthops during multipath

[Joseph Salisbury]

BugLink: http://bugs.launchpad.net/bugs/1738219

== SRU Justification ==
When the 'ignore_routes_with_linkdown' sysctl is set, we should not
consider linkdown nexthops during route lookup.

While the code correctly verifies that the initially selected route
('match') has a carrier, it does not perform the same check in the
subsequent multipath selection, resulting in a potential packet loss.

In case the chosen route does not have a carrier and the sysctl is set,
choose the initially selected route.

This is a regression introduced by commit 35103d11173b in 4.3-rc1.  Commit 
bbfcd7763 resolves this regression and is mainline as of 4.15-rc1.    

== Fix ==
commit bbfcd77631573ac4a9f57eb6169e04256a111bc1
Author: Ido Schimmel <idosch at mellanox.com>
Date:   Tue Nov 21 09:50:12 2017 +0200

    ipv6: Do not consider linkdown nexthops during multipath

== Regression Potential ==
This fix is specific to ipv6 and fixes a current regression.

== Test Case ==
A test kernel was built with this patch and tested by the original bug reporter.
The bug reporter states the test kernel resolved the bug.
Ido Schimmel (1):
  ipv6: Do not consider linkdown nexthops during multipath

 net/ipv6/route.c | 5 +++++
 1 file changed, 5 insertions(+)

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2.7.4