net: openvswitch: silence suspicious RCU usage warning

Silence suspicious RCU usage warning in ovs_flow_tbl_masks_cache_resize()
by replacing rcu_dereference() with rcu_dereference_ovsl().

In addition, when creating a new datapath, make sure it's configured under
the ovs_lock.

Fixes: 9bf24f594c6a ("net: openvswitch: make masks cache size configurable")
Reported-by: syzbot+9a8f8bfcc56e8578016c@syzkaller.appspotmail.com
Signed-off-by: Eelco Chaudron <echaudro@redhat.com>
Link: https://lore.kernel.org/r/160439190002.56943.1418882726496275961.stgit@ebuild
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c
index 832f898..9d6ef6c 100644 (file)
--- a/net/openvswitch/datapath.c
+++ b/net/openvswitch/datapath.c
@@ -1703,13 +1703,13 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info)
        parms.port_no = OVSP_LOCAL;
        parms.upcall_portids = a[OVS_DP_ATTR_UPCALL_PID];
 
-       err = ovs_dp_change(dp, a);
-       if (err)
-               goto err_destroy_meters;
-
        /* So far only local changes have been made, now need the lock. */
        ovs_lock();
 
+       err = ovs_dp_change(dp, a);
+       if (err)
+               goto err_unlock_and_destroy_meters;
+
        vport = new_vport(&parms);
        if (IS_ERR(vport)) {
                err = PTR_ERR(vport);
@@ -1725,8 +1725,7 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info)
                                ovs_dp_reset_user_features(skb, info);
                }
 
-               ovs_unlock();
-               goto err_destroy_meters;
+               goto err_unlock_and_destroy_meters;
        }
 
        err = ovs_dp_cmd_fill_info(dp, reply, info->snd_portid,
@@ -1741,7 +1740,8 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info)
        ovs_notify(&dp_datapath_genl_family, reply, info);
        return 0;
 
-err_destroy_meters:
+err_unlock_and_destroy_meters:
+       ovs_unlock();
        ovs_meters_exit(dp);
 err_destroy_ports:
        kfree(dp->ports);

diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c
index f3486a3..c89c8da 100644 (file)
--- a/net/openvswitch/flow_table.c
+++ b/net/openvswitch/flow_table.c
@@ -390,7 +390,7 @@ static struct mask_cache *tbl_mask_cache_alloc(u32 size)
 }
 int ovs_flow_tbl_masks_cache_resize(struct flow_table *table, u32 size)
 {
-       struct mask_cache *mc = rcu_dereference(table->mask_cache);
+       struct mask_cache *mc = rcu_dereference_ovsl(table->mask_cache);
        struct mask_cache *new;
 
        if (size == mc->cache_size)