From: Tonghao Zhang <xiangxia.m....@gmail.com>
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 <jkn...@google.com>
Reported-at:
https://mail.openvswitch.org/pipermail/ovs-discuss/2020-August/050489.html
Signed-off-by: Tonghao Zhang <xiangxia.m....@gmail.com>
---
v2:
* Change local var coding style
* Add reported and fixed tag
---
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 42f8cc70bb2c..6e47ef7ef036 100644
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -1756,6 +1756,7 @@ 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++) {
@@ -1774,7 +1775,14 @@ 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 8c12675cbb67..e2235849a57e 100644
--- a/net/openvswitch/flow_table.c
+++ b/net/openvswitch/flow_table.c
@@ -473,19 +473,15 @@ 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;
@@ -497,18 +493,16 @@ 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
@@ -523,7 +517,7 @@ void ovs_flow_tbl_destroy(struct flow_table *table)
call_rcu(&mc->rcu, mask_cache_rcu_cb);
call_rcu(&ma->rcu, mask_array_rcu_cb);
- 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,
@@ -641,7 +635,8 @@ 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 74ce48fecba9..6e7d4ac59353 100644
--- a/net/openvswitch/flow_table.h
+++ b/net/openvswitch/flow_table.h
@@ -105,5 +105,8 @@ 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 ovs_flow_masks_rebalance(struct flow_table *table);
+void table_instance_flow_flush(struct flow_table *table,
+ struct table_instance *ti,
+ struct table_instance *ufid_ti);
#endif /* flow_table.h */
--
2.23.0
