[NET]: Set a separate lockdep class for neighbour table's proxy_queue (c2ecba71) · Commits · 戴 / test

Otherwise the following calltrace will lead to a wrong lockdep warning: neigh_proxy_process() `- lock(neigh_table->proxy_queue.lock); arp_redo /* via tbl->proxy_redo */ arp_process neigh_event_ns neigh_update skb_queue_purge `- lock(neighbor->arp_queue.lock); This is not a deadlock actually, as neighbor table's proxy_queue and the neighbor's arp_queue are different queues. Lockdep thinks there is a deadlock as both queues are initialized with skb_queue_head_init() and thus have a common class. Signed-off-by:

David S. Miller <davem@davemloft.net>

include/linux/skbuff.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -619,6 +619,13 @@ static inline void skb_queue_head_init(struct sk_buff_head *list)
		list->qlen = 0;
		}

		static inline void skb_queue_head_init_class(struct sk_buff_head *list,
		struct lock_class_key *class)
		{
		skb_queue_head_init(list);
		lockdep_set_class(&list->lock, class);
		}

		/*
		* Insert an sk_buff at the start of a list.
		*

net/core/neighbour.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -1331,6 +1331,8 @@ void neigh_parms_destroy(struct neigh_parms *parms)
		kfree(parms);
		}

		static struct lock_class_key neigh_table_proxy_queue_class;

		void neigh_table_init_no_netlink(struct neigh_table *tbl)
		{
		unsigned long now = jiffies;
		@@ -1379,7 +1381,8 @@ void neigh_table_init_no_netlink(struct neigh_table *tbl)
		init_timer(&tbl->proxy_timer);
		tbl->proxy_timer.data = (unsigned long)tbl;
		tbl->proxy_timer.function = neigh_proxy_process;
		skb_queue_head_init(&tbl->proxy_queue);
		skb_queue_head_init_class(&tbl->proxy_queue,
		&neigh_table_proxy_queue_class);

		tbl->last_flush = now;
		tbl->last_rand = now + tbl->parms.reachable_time * 20;

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