net: Fix race condition in store_rps_map

[cascardo/linux.git] / net / core / net-sysfs.c

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 194c1d0..39ec694 100644 (file)
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -726,14 +726,17 @@ static ssize_t store_rps_map(struct netdev_rx_queue *queue,
        old_map = rcu_dereference_protected(queue->rps_map,
                                            lockdep_is_held(&rps_map_lock));
        rcu_assign_pointer(queue->rps_map, map);
-       spin_unlock(&rps_map_lock);
 
        if (map)
                static_key_slow_inc(&rps_needed);
-       if (old_map) {
-               kfree_rcu(old_map, rcu);
+       if (old_map)
                static_key_slow_dec(&rps_needed);
-       }
+
+       spin_unlock(&rps_map_lock);
+
+       if (old_map)
+               kfree_rcu(old_map, rcu);
+
        free_cpumask_var(mask);
        return len;
 }