From: John Fastabend <john.fastabend@gmail.com>
Date: Mon, 6 Oct 2014 04:28:20 +0000 (-0700)
Subject: net: sched: cls_cgroup tear down exts and ematch from rcu callback
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=13990f8156862fe945a1a226850a6550c8988a33;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

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>
---

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);
 	}
 }