Commit 6c9bef32 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'inet-fix-defrag-units-dismantle-races' 



Eric Dumazet says:

====================
inet: fix defrag units dismantle races

This series add a new pre_exit() method to struct pernet_operations
to solve a race in defrag units dismantle, without adding extra
delays to netns dismantles.
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 2a54003e d5dd8879

include/net/inet_frag.h

+7 −1
Original line number Diff line number Diff line
@@ -20,7 +20,7 @@ struct fqdir { 


	/* Keep atomic mem on separate cachelines in structs that include it */

	atomic_long_t		mem ____cacheline_aligned_in_smp;

	struct rcu_work		destroy_rwork;

	struct work_struct	destroy_work;

};



/**
@@ -113,6 +113,12 @@ int inet_frags_init(struct inet_frags *); 
void inet_frags_fini(struct inet_frags *);



int fqdir_init(struct fqdir **fqdirp, struct inet_frags *f, struct net *net);



static void inline fqdir_pre_exit(struct fqdir *fqdir)

{

	fqdir->high_thresh = 0; /* prevent creation of new frags */

	fqdir->dead = true;

}

void fqdir_exit(struct fqdir *fqdir);



void inet_frag_kill(struct inet_frag_queue *q);

include/net/ipv6_frag.h

+2 −0
Original line number Diff line number Diff line
@@ -67,6 +67,8 @@ ip6frag_expire_frag_queue(struct net *net, struct frag_queue *fq) 
	struct sk_buff *head;



	rcu_read_lock();

	if (fq->q.fqdir->dead)

		goto out_rcu_unlock;

	spin_lock(&fq->q.lock);



	if (fq->q.flags & INET_FRAG_COMPLETE)

include/net/net_namespace.h

+5 −0
Original line number Diff line number Diff line
@@ -355,8 +355,13 @@ struct pernet_operations { 
	 * synchronize_rcu() related to these pernet_operations,

	 * instead of separate synchronize_rcu() for every net.

	 * Please, avoid synchronize_rcu() at all, where it's possible.

	 *

	 * Note that a combination of pre_exit() and exit() can

	 * be used, since a synchronize_rcu() is guaranteed between

	 * the calls.

	 */

	int (*init)(struct net *net);

	void (*pre_exit)(struct net *net);

	void (*exit)(struct net *net);

	void (*exit_batch)(struct list_head *net_exit_list);

	unsigned int *id;

net/core/net_namespace.c

+28 −0
Original line number Diff line number Diff line
@@ -145,6 +145,17 @@ static void ops_free(const struct pernet_operations *ops, struct net *net) 
	}

}



static void ops_pre_exit_list(const struct pernet_operations *ops,

			      struct list_head *net_exit_list)

{

	struct net *net;



	if (ops->pre_exit) {

		list_for_each_entry(net, net_exit_list, exit_list)

			ops->pre_exit(net);

	}

}



static void ops_exit_list(const struct pernet_operations *ops,

			  struct list_head *net_exit_list)

{
@@ -328,6 +339,12 @@ out_undo: 
	 * for the pernet modules whose init functions did not fail.

	 */

	list_add(&net->exit_list, &net_exit_list);

	saved_ops = ops;

	list_for_each_entry_continue_reverse(ops, &pernet_list, list)

		ops_pre_exit_list(ops, &net_exit_list);



	synchronize_rcu();



	saved_ops = ops;

	list_for_each_entry_continue_reverse(ops, &pernet_list, list)

		ops_exit_list(ops, &net_exit_list);
@@ -541,10 +558,15 @@ static void cleanup_net(struct work_struct *work) 
		list_add_tail(&net->exit_list, &net_exit_list);

	}



	/* Run all of the network namespace pre_exit methods */

	list_for_each_entry_reverse(ops, &pernet_list, list)

		ops_pre_exit_list(ops, &net_exit_list);



	/*

	 * Another CPU might be rcu-iterating the list, wait for it.

	 * This needs to be before calling the exit() notifiers, so

	 * the rcu_barrier() below isn't sufficient alone.

	 * Also the pre_exit() and exit() methods need this barrier.

	 */

	synchronize_rcu();
@@ -1101,6 +1123,8 @@ static int __register_pernet_operations(struct list_head *list, 
out_undo:

	/* If I have an error cleanup all namespaces I initialized */

	list_del(&ops->list);

	ops_pre_exit_list(ops, &net_exit_list);

	synchronize_rcu();

	ops_exit_list(ops, &net_exit_list);

	ops_free_list(ops, &net_exit_list);

	return error;
@@ -1115,6 +1139,8 @@ static void __unregister_pernet_operations(struct pernet_operations *ops) 
	/* See comment in __register_pernet_operations() */

	for_each_net(net)

		list_add_tail(&net->exit_list, &net_exit_list);

	ops_pre_exit_list(ops, &net_exit_list);

	synchronize_rcu();

	ops_exit_list(ops, &net_exit_list);

	ops_free_list(ops, &net_exit_list);

}
@@ -1139,6 +1165,8 @@ static void __unregister_pernet_operations(struct pernet_operations *ops) 
	} else {

		LIST_HEAD(net_exit_list);

		list_add(&init_net.exit_list, &net_exit_list);

		ops_pre_exit_list(ops, &net_exit_list);

		synchronize_rcu();

		ops_exit_list(ops, &net_exit_list);

		ops_free_list(ops, &net_exit_list);

	}

net/ieee802154/6lowpan/reassembly.c

+11 −2
Original line number Diff line number Diff line
@@ -459,6 +459,14 @@ static int __net_init lowpan_frags_init_net(struct net *net) 
	return res;

}



static void __net_exit lowpan_frags_pre_exit_net(struct net *net)

{

	struct netns_ieee802154_lowpan *ieee802154_lowpan =

		net_ieee802154_lowpan(net);



	fqdir_pre_exit(ieee802154_lowpan->fqdir);

}



static void __net_exit lowpan_frags_exit_net(struct net *net)

{

	struct netns_ieee802154_lowpan *ieee802154_lowpan =
@@ -470,6 +478,7 @@ static void __net_exit lowpan_frags_exit_net(struct net *net) 


static struct pernet_operations lowpan_frags_ops = {

	.init		= lowpan_frags_init_net,

	.pre_exit	= lowpan_frags_pre_exit_net,

	.exit		= lowpan_frags_exit_net,

};

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