DST_NOCOUNT in dst_entry::flags tracks whether the entry counts toward route cache size (net->ipv6.sysctl.ip6_rt_max_size).
If the flag is NOT set, dst_ops::pcpuc_entries counter is incremented in dist_init() and decremented in dst_destroy(). This flag is tied to allocation/deallocation of dst_entry and should not be copied from another dst/route. Otherwise it can happen that dst_ops::pcpuc_entries counter grows until no new routes can be allocated because the counter reached ip6_rt_max_size due to DST_NOCOUNT not set and thus no counter decrements on gc-ed routes. Fixes: 3b6761d18bc1 ("net/ipv6: Move dst flags to booleans in fib entries") Cc: David Ahern <dsah...@gmail.com> Acked-by: Wei Wang <wei...@google.com> Signed-off-by: Peter Oskolkov <p...@google.com> --- net/ipv6/route.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 3eed045c65a5..480a79f47c52 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -946,8 +946,6 @@ static void ip6_rt_init_dst_reject(struct rt6_info *rt, struct fib6_info *ort) static void ip6_rt_init_dst(struct rt6_info *rt, struct fib6_info *ort) { - rt->dst.flags |= fib6_info_dst_flags(ort); - if (ort->fib6_flags & RTF_REJECT) { ip6_rt_init_dst_reject(rt, ort); return; -- 2.19.0.397.gdd90340f6a-goog