On Wed, Feb 14, 2018 at 5:24 PM, Steffen Klassert <steffen.klass...@secunet.com> wrote: > On Tue, Feb 13, 2018 at 08:23:14PM +0200, Eyal Birger wrote: >> Hi Xin Long, >> >> On Tue, 13 Feb 2018 23:18:14 +0800 >> Xin Long <lucien....@gmail.com> wrote: >> >> > On Tue, Feb 13, 2018 at 6:54 PM, Eyal Birger <eyal.bir...@gmail.com> >> > wrote: >> > > In setups like the following: >> > > >> > > Host A -- Host B >> > > tun0 -- ipsec -- eth0 -- eth0 -- ipsec -- tun0 >> > > >> > > where tun0 are tunnel devices using dst_cache (ipip, ipip6, etc...). >> > > >> > > Unregistration of an underlying eth0 device leads to the following >> > > log messages: >> > > >> > > unregister_netdevice: waiting for eth0 to become free. Usage count >> > > = 2 >> > > >> > > This is since xfrm dsts device references are not released upon >> > > device unregistration when the xfrm dst is cached in a dst_cache. >> > > >> > > This issue was first introduced in commit 52df157f17e5 >> > > ("xfrm: take refcnt of dst when creating struct xfrm_dst bundle") >> > > as part of an effort to remove routing garbage collection. >> > > >> > > Several approaches for fixing this were discussed in [1]; this >> > > commit keeps track of allocated xdsts and releases their device >> > > references on a netdev unregister/down events. >> > > >> > > Signed-off-by: Eyal Birger <eyal.bir...@gmail.com> >> > > Fixes: 52df157f17e5 ("xfrm: take refcnt of dst when creating struct >> > > xfrm_dst bundle") >> > I had another fix [1] for this issue in my local tree. >> > That reuses uncached_list to track xdsts, and fewer job to do for >> > this. As naturally uncached_list is already the list that is supposed >> > to do this job. We don't have to introduce a new list and members. >> > >> > [1] https://paste.fedoraproject.org/paste/X8FQzEXjGXQBTKAVLnDn4w >> >> I have tested your patch and it resolves the issue described. >> I like not having to introduce a new list and lock. > > Me too. This looks like the best of all proposed solutions. Cool.
> >> >> Small note: I think you need to increase net->ipv6.rt6_stats->fib_rt_uncache >> when adding to the IPv6 uncached list from the xfrm code. You're right, thanks for the note. > > Xing, plaese incorporate the review and submit the patch. Will post soon. > > Thanks!