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As > the base prefix is deprecated already, the generation fails, burning the > retry counter for temporary address generation of that prefix. > > When the router eventually restores the prefix, the temporary address > becomes active again. However, once it naturally expires, the kernel > sees the exhausted retry limit and permanently stops generating new > privacy addresses. It's not clear to me to which "retry counter" you are referring to. Are you referring to the counter of the temporary address or to that of the "public address" from which it was generated? AFAICT, in the case of temporary addresses (those w/o "mngtmpaddr") this isn't really a counter, but a boolean that tells you if an address was already spawned from this address. > > Fix this by verifying that the base prefix has sufficient preferred > lifetime remaining before attempting to generate a new temporary > address. This prevents the worker from burning through its retry counter > during temporary network deprecation events like a router reboot. Again, I think that "retry counter" here is confusing. IIUC, what happens is that the kernel marks the temporary address as having spawned an address ('ifp->regen_count++'), then tries to spawn an address by calling ipv6_create_tempaddr(), which fails because the preferred lifetime of the public address is 0. > > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") > Reported-by: Łukasz Stelmach > Closes: https://lore.kernel.org/netdev/87340td30q.fsf%25steelman@post.pl/ > Signed-off-by: Fernando Fernandez Mancera > --- > net/ipv6/addrconf.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c > index 5476b6536eb7..f6a3d9da3cb1 100644 > --- a/net/ipv6/addrconf.c > +++ b/net/ipv6/addrconf.c > @@ -4654,9 +4654,11 @@ static void addrconf_verify_rtnl(struct net *net) > !ifp->regen_count && ifp->ifpub) { > /* This is a non-regenerated temporary addr. */ > > + unsigned long pub_age = (now - READ_ONCE(ifp->ifpub->tstamp)) / HZ; > unsigned long regen_advance = ipv6_get_regen_advance(ifp->idev); > > - if (age + regen_advance >= ifp->prefered_lft) { > + if (age + regen_advance >= ifp->prefered_lft && > + pub_age + regen_advance < READ_ONCE(ifp->ifpub->prefered_lft)) { > struct inet6_ifaddr *ifpub = ifp->ifpub; > if (time_before(ifp->tstamp + ifp->prefered_lft * HZ, next)) > next = ifp->tstamp + ifp->prefered_lft * HZ; > -- > 2.53.0 >