On Wed, May 02, 2018 at 08:21:06PM +0300, Ido Schimmel wrote:
> On Wed, May 02, 2018 at 09:43:50AM -0700, Eric Dumazet wrote:
> >
> >
> > On 01/09/2018 07:43 PM, David Ahern wrote:
> > > On 1/9/18 7:40 AM, Ido Schimmel wrote:
> > >> Before we convert IPv6 to use hash-threshold instead of modulo-N, we
> > >> first need each nexthop to store its region boundary in the hash
> > >> function's output space.
> > >>
> > >> The boundary is calculated by dividing the output space equally between
> > >> the different active nexthops. That is, nexthops that are not dead or
> > >> linkdown.
> > >>
> > >> The boundaries are rebalanced whenever a nexthop is added or removed to
> > >> a multipath route and whenever a nexthop becomes active or inactive.
> > >>
> > >> Signed-off-by: Ido Schimmel <ido...@mellanox.com>
> > >> ---
> > >> include/net/ip6_fib.h | 1 +
> > >> include/net/ip6_route.h | 7 ++++
> > >> net/ipv6/ip6_fib.c | 8 ++---
> > >> net/ipv6/route.c | 96
> > >> +++++++++++++++++++++++++++++++++++++++++++++++++
> > >> 4 files changed, 106 insertions(+), 6 deletions(-)
> > >>
> > >
> > > LGTM.
> > > Acked-by: David Ahern <dsah...@gmail.com>
> > >
> >
> > For some reason I have a divide by zero error booting my hosts with latest
> > net tree.
> >
> > What guarantee do we have that total is not zero when rt6_upper_bound_set()
> > is called ?
>
> Thanks for the report, Eric. I believe I didn't cover all the cases and
> 'rt6i_nh_weight' might be 0 is some cases. I'll try to reproduce and
> work on a fix.
Hmmm, I think it's due to commit edd7ceb78296 ("ipv6: Allow non-gateway
ECMP for IPv6") which allows routes without a gateway (such as those
configured using slaac) to have siblings.
Can you please check if reverting the patch / applying the below fixes
the issue?
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index f4d61736c41a..129dd4f4b264 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -3606,6 +3606,7 @@ struct rt6_info *addrconf_dst_alloc(struct inet6_dev
*idev,
rt->dst.input = ip6_input;
rt->dst.output = ip6_output;
rt->rt6i_idev = idev;
+ rt->rt6i_nh_weight = 1;
rt->rt6i_protocol = RTPROT_KERNEL;
rt->rt6i_flags = RTF_UP | RTF_NONEXTHOP;
