6.1-stable review patch. If anyone has any objections, please let me know.
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From: Vlad Buslov vladbu@nvidia.com
commit a63b6622120cd03a304796dbccb80655b3a21798 upstream.
Current nf_flow_is_outdated() implementation considers any flow table flow which state diverged from its underlying CT connection status for teardown which can be problematic in the following cases:
- Flow has never been offloaded to hardware in the first place either because flow table has hardware offload disabled (flag NF_FLOWTABLE_HW_OFFLOAD is not set) or because it is still pending on 'add' workqueue to be offloaded for the first time. The former is incorrect, the later generates excessive deletions and additions of flows.
- Flow is already pending to be updated on the workqueue. Tearing down such flows will also generate excessive removals from the flow table, especially on highly loaded system where the latency to re-offload a flow via 'add' workqueue can be quite high.
When considering a flow for teardown as outdated verify that it is both offloaded to hardware and doesn't have any pending updates.
Fixes: 41f2c7c342d3 ("net/sched: act_ct: Fix promotion of offloaded unreplied tuple") Reviewed-by: Paul Blakey paulb@nvidia.com Signed-off-by: Vlad Buslov vladbu@nvidia.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sched/act_ct.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/net/sched/act_ct.c +++ b/net/sched/act_ct.c @@ -277,6 +277,8 @@ err_nat: static bool tcf_ct_flow_is_outdated(const struct flow_offload *flow) { return test_bit(IPS_SEEN_REPLY_BIT, &flow->ct->status) && + test_bit(IPS_HW_OFFLOAD_BIT, &flow->ct->status) && + !test_bit(NF_FLOW_HW_PENDING, &flow->flags) && !test_bit(NF_FLOW_HW_ESTABLISHED, &flow->flags); }