[BRIDGE]: Missing rtnl.

Writing to /sys/class/net/brX/bridge/stp_state causes a warning because
RTNL is not held when call br_stp_if.c

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 0 deletions

diff --git a/net/bridge/br_sysfs_br.c b/net/bridge/br_sysfs_br.c
index 7ec0b76cdd27..33c6c4a7c689 100644
--- a/net/bridge/br_sysfs_br.c
+++ b/net/bridge/br_sysfs_br.c
@@ -149,9 +149,11 @@ static ssize_t show_stp_state(struct device *d,
 
 static void set_stp_state(struct net_bridge *br, unsigned long val)
 {
+        rtnl_lock();
         spin_unlock_bh(&br->lock);
         br_stp_set_enabled(br, val);
         spin_lock_bh(&br->lock);
+        rtnl_unlock();
 }
 
 static ssize_t store_stp_state(struct device *d,