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

[Seth Forshee]

On Fri, Dec 15, 2017 at 09:40:09AM -0500, Joseph Salisbury wrote:
> 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.

Acked-by: Seth Forshee <seth.forshee at canonical.com>

Applied to bionic/master-next, thanks!