net: sched: cls_cgroup tear down exts and ematch from rcu callback

It is not RCU safe to destroy the action chain while there
is a possibility of readers accessing it. Move this code
into the rcu callback using the same rcu callback used in the
code patch to make a change to head.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Acked-by: Cong Wang <cwang@twopensource.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 3 deletions

diff --git a/net/sched/cls_cgroup.c b/net/sched/cls_cgroup.c
index 2f77a89655dc..d61a801222c1 100644
--- a/net/sched/cls_cgroup.c
+++ b/net/sched/cls_cgroup.c
@@ -156,10 +156,8 @@ static void cls_cgroup_destroy(struct tcf_proto *tp)
         struct cls_cgroup_head *head = rtnl_dereference(tp->root);
 
         if (head) {
-                tcf_exts_destroy(&head->exts);
-                tcf_em_tree_destroy(&head->ematches);
                 RCU_INIT_POINTER(tp->root, NULL);
-                kfree_rcu(head, rcu);
+                call_rcu(&head->rcu, cls_cgroup_destroy_rcu);
         }
 }