net/sched: fix filter flushing

When user instructs to remove all filters from chain, we cannot destroy the chain as other actions may hold a reference. Also the put in errout would try to destroy it again. So instead, just walk the chain and remove all existing filters. Fixes: 5bc1701 ("net: sched: introduce multichain support for filters") Signed-off-by: Jiri Pirko <[email protected]> Acked-by: Cong Wang <[email protected]> Signed-off-by: David S. Miller <[email protected]>
mkrufky · May 23, 2017 · f93e1cd · f93e1cd
1 parent 31efcc2
commit f93e1cd
Showing 1 changed file with 10 additions and 3 deletions.
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c
@@ -201,15 +201,22 @@ static struct tcf_chain *tcf_chain_create(struct tcf_block *block,
 	return chain;
 }
 
-static void tcf_chain_destroy(struct tcf_chain *chain)
+static void tcf_chain_flush(struct tcf_chain *chain)
 {
 	struct tcf_proto *tp;
 
-	list_del(&chain->list);
+	if (*chain->p_filter_chain)
+		RCU_INIT_POINTER(*chain->p_filter_chain, NULL);
 	while ((tp = rtnl_dereference(chain->filter_chain)) != NULL) {
 		RCU_INIT_POINTER(chain->filter_chain, tp->next);
 		tcf_proto_destroy(tp);
 	}
+}
+
+static void tcf_chain_destroy(struct tcf_chain *chain)
+{
+	list_del(&chain->list);
+	tcf_chain_flush(chain);
 	kfree(chain);
 }
 
@@ -510,7 +517,7 @@ static int tc_ctl_tfilter(struct sk_buff *skb, struct nlmsghdr *n,
 
 	if (n->nlmsg_type == RTM_DELTFILTER && prio == 0) {
 		tfilter_notify_chain(net, skb, n, chain, RTM_DELTFILTER);
-		tcf_chain_destroy(chain);
+		tcf_chain_flush(chain);
 		err = 0;
 		goto errout;
 	}