From: Tonghao Zhang xiangxia.m.yue@gmail.com

[ Upstream commit 77b981c82c1df7c7ad32a046f17f007450b46954 ]

Backport this commit to 5.6.14 - 5.8.3.

To avoid some issues, for example RCU usage warning and double free, we should flush the flows under ovs_lock. This patch refactors table_instance_destroy and introduces table_instance_flow_flush which can be invoked by __dp_destroy or ovs_flow_tbl_flush.

Fixes: 50b0e61b32ee ("net: openvswitch: fix possible memleak on destroy flow-table") Reported-by: Johan Knöös jknoos@google.com Reported-at: https://mail.openvswitch.org/pipermail/ovs-discuss/2020-August/050489.html Signed-off-by: Tonghao Zhang xiangxia.m.yue@gmail.com Reviewed-by: Cong Wang xiyou.wangcong@gmail.com Signed-off-by: David S. Miller davem@davemloft.net --- net/openvswitch/datapath.c | 10 +++++++++- net/openvswitch/flow_table.c | 35 +++++++++++++++-------------------- net/openvswitch/flow_table.h | 3 +++ 3 files changed, 27 insertions(+), 21 deletions(-)

diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c index 94b024534987..03b81aa99975 100644 --- a/net/openvswitch/datapath.c +++ b/net/openvswitch/datapath.c @@ -1736,6 +1736,7 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info) /* Called with ovs_mutex. */ static void __dp_destroy(struct datapath *dp) { + struct flow_table *table = &dp->table; int i;

for (i = 0; i < DP_VPORT_HASH_BUCKETS; i++) { @@ -1754,7 +1755,14 @@ static void __dp_destroy(struct datapath *dp) */ ovs_dp_detach_port(ovs_vport_ovsl(dp, OVSP_LOCAL));

- /* RCU destroy the flow table */ + /* Flush sw_flow in the tables. RCU cb only releases resource + * such as dp, ports and tables. That may avoid some issues + * such as RCU usage warning. + */ + table_instance_flow_flush(table, ovsl_dereference(table->ti), + ovsl_dereference(table->ufid_ti)); + + /* RCU destroy the ports, meters and flow tables. */ call_rcu(&dp->rcu, destroy_dp_rcu); }

diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c index 2398d7238300..f198bbb0c517 100644 --- a/net/openvswitch/flow_table.c +++ b/net/openvswitch/flow_table.c @@ -345,19 +345,15 @@ static void table_instance_flow_free(struct flow_table *table, flow_mask_remove(table, flow->mask); }

-static void table_instance_destroy(struct flow_table *table, - struct table_instance *ti, - struct table_instance *ufid_ti, - bool deferred) +/* Must be called with OVS mutex held. */ +void table_instance_flow_flush(struct flow_table *table, + struct table_instance *ti, + struct table_instance *ufid_ti) { int i;

- if (!ti) - return; - - BUG_ON(!ufid_ti); if (ti->keep_flows) - goto skip_flows; + return;

for (i = 0; i < ti->n_buckets; i++) { struct sw_flow *flow; @@ -369,18 +365,16 @@ static void table_instance_destroy(struct flow_table *table,

table_instance_flow_free(table, ti, ufid_ti, flow, false); - ovs_flow_free(flow, deferred); + ovs_flow_free(flow, true); } } +}

-skip_flows: - if (deferred) { - call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb); - call_rcu(&ufid_ti->rcu, flow_tbl_destroy_rcu_cb); - } else { - __table_instance_destroy(ti); - __table_instance_destroy(ufid_ti); - } +static void table_instance_destroy(struct table_instance *ti, + struct table_instance *ufid_ti) +{ + call_rcu(&ti->rcu, flow_tbl_destroy_rcu_cb); + call_rcu(&ufid_ti->rcu, flow_tbl_destroy_rcu_cb); }

/* No need for locking this function is called from RCU callback or @@ -393,7 +387,7 @@ void ovs_flow_tbl_destroy(struct flow_table *table)

free_percpu(table->mask_cache); kfree_rcu(rcu_dereference_raw(table->mask_array), rcu); - table_instance_destroy(table, ti, ufid_ti, false); + table_instance_destroy(ti, ufid_ti); }

struct sw_flow *ovs_flow_tbl_dump_next(struct table_instance *ti, @@ -511,7 +505,8 @@ int ovs_flow_tbl_flush(struct flow_table *flow_table) flow_table->count = 0; flow_table->ufid_count = 0;

- table_instance_destroy(flow_table, old_ti, old_ufid_ti, true); + table_instance_flow_flush(flow_table, old_ti, old_ufid_ti); + table_instance_destroy(old_ti, old_ufid_ti); return 0;

err_free_ti: diff --git a/net/openvswitch/flow_table.h b/net/openvswitch/flow_table.h index 8a5cea6ae111..8ea8fc957377 100644 --- a/net/openvswitch/flow_table.h +++ b/net/openvswitch/flow_table.h @@ -86,4 +86,7 @@ bool ovs_flow_cmp(const struct sw_flow *, const struct sw_flow_match *);

void ovs_flow_mask_key(struct sw_flow_key *dst, const struct sw_flow_key *src, bool full, const struct sw_flow_mask *mask); +void table_instance_flow_flush(struct flow_table *table, + struct table_instance *ti, + struct table_instance *ufid_ti); #endif /* flow_table.h */