Hi,
On Mon, 2019-03-18 at 14:30 -0700, Wei Wang wrote:
> On Mon, Mar 18, 2019 at 12:48 PM David Ahern <d...@cumulusnetworks.com> wrote:
> > On 3/18/19 12:36 PM, Xin Long wrote:
> > > diff --git a/net/ipv6/route.c b/net/ipv6/route.c
> > > index 4ef4bbd..754777d 100644
> > > --- a/net/ipv6/route.c
> > > +++ b/net/ipv6/route.c
> > > @@ -1040,13 +1040,17 @@ static struct rt6_info *ip6_create_rt_rcu(struct
> > > fib6_info *rt)
> > > struct rt6_info *nrt;
> > >
> > > if (!fib6_info_hold_safe(rt))
> > > - return NULL;
> > > + goto fallback;
> > >
> > > nrt = ip6_dst_alloc(dev_net(dev), dev, flags);
> > > - if (nrt)
> > > + if (nrt) {
> > > ip6_rt_copy_init(nrt, rt);
> > > - else
> > > + } else {
> > > fib6_info_release(rt);
> > > +fallback:
> > > + nrt = dev_net(dev)->ipv6.ip6_null_entry;
> > > + dst_hold(&nrt->dst);
> > > + }
> > >
> > > return nrt;
> > > }
> >
> > It seems appropriate for ip6_create_rt_rcu to always return an rt6_info
> > given its use and v6 design. Since ip6_dst_alloc can also fail
> > (e.g.,
> > exceed gc_thresh) the fallback case should apply to both.
>
> Agree. We should take care of ip6_dst_alloc() as well.
AFAICS, if ip6_dst_alloc() fails/returns a NULL ptr, with this patch we
do enter the fallback path (and return a valid rt6_info). I think your
concerns are already addressed, what I'm missing ?!?
Thanks,
Paolo
