[PATCH net] team: call RCU read lock when walking the port_list

[Hangbin Liu]

Before reading the team port list, we need to acquire the RCU read lock.
Also change list_for_each_entry() to list_for_each_entry_rcu().

Fixes: 9ed68ca0d90b ("team: add ethtool get_link_ksettings")
Reported-by: Paolo Abeni <pab...@redhat.com>
Signed-off-by: Hangbin Liu <liuhang...@gmail.com>
Acked-by: Paolo Abeni <pab...@redhat.com>
---
 drivers/net/team/team.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/net/team/team.c b/drivers/net/team/team.c
index e8089def5a46..cb1d5fe60c31 100644
--- a/drivers/net/team/team.c
+++ b/drivers/net/team/team.c
@@ -2066,7 +2066,8 @@ static int team_ethtool_get_link_ksettings(struct 
net_device *dev,
        cmd->base.duplex = DUPLEX_UNKNOWN;
        cmd->base.port = PORT_OTHER;
 
-       list_for_each_entry(port, &team->port_list, list) {
+       rcu_read_lock();
+       list_for_each_entry_rcu(port, &team->port_list, list) {
                if (team_port_txable(port)) {
                        if (port->state.speed != SPEED_UNKNOWN)
                                speed += port->state.speed;
@@ -2075,6 +2076,8 @@ static int team_ethtool_get_link_ksettings(struct 
net_device *dev,
                                cmd->base.duplex = port->state.duplex;
                }
        }
+       rcu_read_unlock();
+
        cmd->base.speed = speed ? : SPEED_UNKNOWN;
 
        return 0;
-- 
2.19.2