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Commit c15b1cca authored by Hannes Frederic Sowa's avatar Hannes Frederic Sowa Committed by David S. Miller
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ipv6: move DAD and addrconf_verify processing to workqueue 



addrconf_join_solict and addrconf_join_anycast may cause actions which
need rtnl locked, especially on first address creation.

A new DAD state is introduced which defers processing of the initial
DAD processing into a workqueue.

To get rtnl lock we need to push the code paths which depend on those
calls up to workqueues, specifically addrconf_verify and the DAD
processing.

(v2)
addrconf_dad_failure needs to be queued up to the workqueue, too. This
patch introduces a new DAD state and stop the DAD processing in the
workqueue (this is because of the possible ipv6_del_addr processing
which removes the solicited multicast address from the device).

addrconf_verify_lock is removed, too. After the transition it is not
needed any more.

As we are not processing in bottom half anymore we need to be a bit more
careful about disabling bottom half out when we lock spin_locks which are also
used in bh.

Relevant backtrace:
[  541.030090] RTNL: assertion failed at net/core/dev.c (4496)
[  541.031143] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G           O 3.10.33-1-amd64-vyatta #1
[  541.031145] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2007
[  541.031146]  ffffffff8148a9f0 000000000000002f ffffffff813c98c1 ffff88007c4451f8
[  541.031148]  0000000000000000 0000000000000000 ffffffff813d3540 ffff88007fc03d18
[  541.031150]  0000880000000006 ffff88007c445000 ffffffffa0194160 0000000000000000
[  541.031152] Call Trace:
[  541.031153]  <IRQ>  [<ffffffff8148a9f0>] ? dump_stack+0xd/0x17
[  541.031180]  [<ffffffff813c98c1>] ? __dev_set_promiscuity+0x101/0x180
[  541.031183]  [<ffffffff813d3540>] ? __hw_addr_create_ex+0x60/0xc0
[  541.031185]  [<ffffffff813cfe1a>] ? __dev_set_rx_mode+0xaa/0xc0
[  541.031189]  [<ffffffff813d3a81>] ? __dev_mc_add+0x61/0x90
[  541.031198]  [<ffffffffa01dcf9c>] ? igmp6_group_added+0xfc/0x1a0 [ipv6]
[  541.031208]  [<ffffffff8111237b>] ? kmem_cache_alloc+0xcb/0xd0
[  541.031212]  [<ffffffffa01ddcd7>] ? ipv6_dev_mc_inc+0x267/0x300 [ipv6]
[  541.031216]  [<ffffffffa01c2fae>] ? addrconf_join_solict+0x2e/0x40 [ipv6]
[  541.031219]  [<ffffffffa01ba2e9>] ? ipv6_dev_ac_inc+0x159/0x1f0 [ipv6]
[  541.031223]  [<ffffffffa01c0772>] ? addrconf_join_anycast+0x92/0xa0 [ipv6]
[  541.031226]  [<ffffffffa01c311e>] ? __ipv6_ifa_notify+0x11e/0x1e0 [ipv6]
[  541.031229]  [<ffffffffa01c3213>] ? ipv6_ifa_notify+0x33/0x50 [ipv6]
[  541.031233]  [<ffffffffa01c36c8>] ? addrconf_dad_completed+0x28/0x100 [ipv6]
[  541.031241]  [<ffffffff81075c1d>] ? task_cputime+0x2d/0x50
[  541.031244]  [<ffffffffa01c38d6>] ? addrconf_dad_timer+0x136/0x150 [ipv6]
[  541.031247]  [<ffffffffa01c37a0>] ? addrconf_dad_completed+0x100/0x100 [ipv6]
[  541.031255]  [<ffffffff8105313a>] ? call_timer_fn.isra.22+0x2a/0x90
[  541.031258]  [<ffffffffa01c37a0>] ? addrconf_dad_completed+0x100/0x100 [ipv6]

Hunks and backtrace stolen from a patch by Stephen Hemminger.

Reported-by: default avatarStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: default avatarStephen Hemminger <stephen@networkplumber.org>
Signed-off-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent e2a1d3e4

include/net/if_inet6.h

+3 −1
Original line number Diff line number Diff line
@@ -31,8 +31,10 @@ 
#define IF_PREFIX_AUTOCONF	0x02



enum {

	INET6_IFADDR_STATE_PREDAD,

	INET6_IFADDR_STATE_DAD,

	INET6_IFADDR_STATE_POSTDAD,

	INET6_IFADDR_STATE_ERRDAD,

	INET6_IFADDR_STATE_UP,

	INET6_IFADDR_STATE_DEAD,

};
@@ -58,7 +60,7 @@ struct inet6_ifaddr { 
	unsigned long		cstamp;	/* created timestamp */

	unsigned long		tstamp; /* updated timestamp */



	struct timer_list	dad_timer;

	struct delayed_work	dad_work;



	struct inet6_dev	*idev;

	struct rt6_info		*rt;

net/ipv6/addrconf.c

+142 −51
Original line number Diff line number Diff line
@@ -133,10 +133,12 @@ static int ipv6_count_addresses(struct inet6_dev *idev); 
static struct hlist_head inet6_addr_lst[IN6_ADDR_HSIZE];

static DEFINE_SPINLOCK(addrconf_hash_lock);



static void addrconf_verify(unsigned long);

static void addrconf_verify(void);

static void addrconf_verify_rtnl(void);

static void addrconf_verify_work(struct work_struct *);



static DEFINE_TIMER(addr_chk_timer, addrconf_verify, 0, 0);

static DEFINE_SPINLOCK(addrconf_verify_lock);

static struct workqueue_struct *addrconf_wq;

static DECLARE_DELAYED_WORK(addr_chk_work, addrconf_verify_work);



static void addrconf_join_anycast(struct inet6_ifaddr *ifp);

static void addrconf_leave_anycast(struct inet6_ifaddr *ifp);
@@ -151,7 +153,7 @@ static struct rt6_info *addrconf_get_prefix_route(const struct in6_addr *pfx, 
						  u32 flags, u32 noflags);



static void addrconf_dad_start(struct inet6_ifaddr *ifp);

static void addrconf_dad_timer(unsigned long data);

static void addrconf_dad_work(struct work_struct *w);

static void addrconf_dad_completed(struct inet6_ifaddr *ifp);

static void addrconf_dad_run(struct inet6_dev *idev);

static void addrconf_rs_timer(unsigned long data);
@@ -247,9 +249,9 @@ static void addrconf_del_rs_timer(struct inet6_dev *idev) 
		__in6_dev_put(idev);

}



static void addrconf_del_dad_timer(struct inet6_ifaddr *ifp)

static void addrconf_del_dad_work(struct inet6_ifaddr *ifp)

{

	if (del_timer(&ifp->dad_timer))

	if (cancel_delayed_work(&ifp->dad_work))

		__in6_ifa_put(ifp);

}
@@ -261,12 +263,12 @@ static void addrconf_mod_rs_timer(struct inet6_dev *idev, 
	mod_timer(&idev->rs_timer, jiffies + when);

}



static void addrconf_mod_dad_timer(struct inet6_ifaddr *ifp,

				   unsigned long when)

static void addrconf_mod_dad_work(struct inet6_ifaddr *ifp,

				   unsigned long delay)

{

	if (!timer_pending(&ifp->dad_timer))

	if (!delayed_work_pending(&ifp->dad_work))

		in6_ifa_hold(ifp);

	mod_timer(&ifp->dad_timer, jiffies + when);

	mod_delayed_work(addrconf_wq, &ifp->dad_work, delay);

}



static int snmp6_alloc_dev(struct inet6_dev *idev)
@@ -751,8 +753,9 @@ void inet6_ifa_finish_destroy(struct inet6_ifaddr *ifp) 


	in6_dev_put(ifp->idev);



	if (del_timer(&ifp->dad_timer))

		pr_notice("Timer is still running, when freeing ifa=%p\n", ifp);

	if (cancel_delayed_work(&ifp->dad_work))

		pr_notice("delayed DAD work was pending while freeing ifa=%p\n",

			  ifp);



	if (ifp->state != INET6_IFADDR_STATE_DEAD) {

		pr_warn("Freeing alive inet6 address %p\n", ifp);
@@ -849,8 +852,7 @@ ipv6_add_addr(struct inet6_dev *idev, const struct in6_addr *addr, 


	spin_lock_init(&ifa->lock);

	spin_lock_init(&ifa->state_lock);

	setup_timer(&ifa->dad_timer, addrconf_dad_timer,

		    (unsigned long)ifa);

	INIT_DELAYED_WORK(&ifa->dad_work, addrconf_dad_work);

	INIT_HLIST_NODE(&ifa->addr_lst);

	ifa->scope = scope;

	ifa->prefix_len = pfxlen;
@@ -990,6 +992,8 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp) 
	enum cleanup_prefix_rt_t action = CLEANUP_PREFIX_RT_NOP;

	unsigned long expires;



	ASSERT_RTNL();



	spin_lock_bh(&ifp->state_lock);

	state = ifp->state;

	ifp->state = INET6_IFADDR_STATE_DEAD;
@@ -1021,7 +1025,7 @@ static void ipv6_del_addr(struct inet6_ifaddr *ifp) 


	write_unlock_bh(&ifp->idev->lock);



	addrconf_del_dad_timer(ifp);

	addrconf_del_dad_work(ifp);



	ipv6_ifa_notify(RTM_DELADDR, ifp);
@@ -1604,7 +1608,7 @@ static void addrconf_dad_stop(struct inet6_ifaddr *ifp, int dad_failed) 
{

	if (ifp->flags&IFA_F_PERMANENT) {

		spin_lock_bh(&ifp->lock);

		addrconf_del_dad_timer(ifp);

		addrconf_del_dad_work(ifp);

		ifp->flags |= IFA_F_TENTATIVE;

		if (dad_failed)

			ifp->flags |= IFA_F_DADFAILED;
@@ -1625,20 +1629,21 @@ static void addrconf_dad_stop(struct inet6_ifaddr *ifp, int dad_failed) 
			spin_unlock_bh(&ifp->lock);

		}

		ipv6_del_addr(ifp);

	} else

	} else {

		ipv6_del_addr(ifp);

	}

}



static int addrconf_dad_end(struct inet6_ifaddr *ifp)

{

	int err = -ENOENT;



	spin_lock(&ifp->state_lock);

	spin_lock_bh(&ifp->state_lock);

	if (ifp->state == INET6_IFADDR_STATE_DAD) {

		ifp->state = INET6_IFADDR_STATE_POSTDAD;

		err = 0;

	}

	spin_unlock(&ifp->state_lock);

	spin_unlock_bh(&ifp->state_lock);



	return err;

}
@@ -1671,7 +1676,12 @@ void addrconf_dad_failure(struct inet6_ifaddr *ifp) 
		}

	}



	addrconf_dad_stop(ifp, 1);

	spin_lock_bh(&ifp->state_lock);

	/* transition from _POSTDAD to _ERRDAD */

	ifp->state = INET6_IFADDR_STATE_ERRDAD;

	spin_unlock_bh(&ifp->state_lock);



	addrconf_mod_dad_work(ifp, 0);

}



/* Join to solicited addr multicast group. */
@@ -1680,6 +1690,8 @@ void addrconf_join_solict(struct net_device *dev, const struct in6_addr *addr) 
{

	struct in6_addr maddr;



	ASSERT_RTNL();



	if (dev->flags&(IFF_LOOPBACK|IFF_NOARP))

		return;
@@ -1691,6 +1703,8 @@ void addrconf_leave_solict(struct inet6_dev *idev, const struct in6_addr *addr) 
{

	struct in6_addr maddr;



	ASSERT_RTNL();



	if (idev->dev->flags&(IFF_LOOPBACK|IFF_NOARP))

		return;
@@ -1701,6 +1715,9 @@ void addrconf_leave_solict(struct inet6_dev *idev, const struct in6_addr *addr) 
static void addrconf_join_anycast(struct inet6_ifaddr *ifp)

{

	struct in6_addr addr;



	ASSERT_RTNL();



	if (ifp->prefix_len >= 127) /* RFC 6164 */

		return;

	ipv6_addr_prefix(&addr, &ifp->addr, ifp->prefix_len);
@@ -1712,6 +1729,9 @@ static void addrconf_join_anycast(struct inet6_ifaddr *ifp) 
static void addrconf_leave_anycast(struct inet6_ifaddr *ifp)

{

	struct in6_addr addr;



	ASSERT_RTNL();



	if (ifp->prefix_len >= 127) /* RFC 6164 */

		return;

	ipv6_addr_prefix(&addr, &ifp->addr, ifp->prefix_len);
@@ -2271,11 +2291,13 @@ ok: 
				return;

			}



			ifp->flags |= IFA_F_MANAGETEMPADDR;

			update_lft = 0;

			create = 1;

			spin_lock_bh(&ifp->lock);

			ifp->flags |= IFA_F_MANAGETEMPADDR;

			ifp->cstamp = jiffies;

			ifp->tokenized = tokenized;

			spin_unlock_bh(&ifp->lock);

			addrconf_dad_start(ifp);

		}
@@ -2326,7 +2348,7 @@ ok: 
					 create, now);



			in6_ifa_put(ifp);

			addrconf_verify(0);

			addrconf_verify();

		}

	}

	inet6_prefix_notify(RTM_NEWPREFIX, in6_dev, pinfo);
@@ -2475,7 +2497,7 @@ static int inet6_addr_add(struct net *net, int ifindex, 
			manage_tempaddrs(idev, ifp, valid_lft, prefered_lft,

					 true, jiffies);

		in6_ifa_put(ifp);

		addrconf_verify(0);

		addrconf_verify_rtnl();

		return 0;

	}
@@ -3011,7 +3033,7 @@ static int addrconf_ifdown(struct net_device *dev, int how) 
		hlist_for_each_entry_rcu(ifa, h, addr_lst) {

			if (ifa->idev == idev) {

				hlist_del_init_rcu(&ifa->addr_lst);

				addrconf_del_dad_timer(ifa);

				addrconf_del_dad_work(ifa);

				goto restart;

			}

		}
@@ -3049,7 +3071,7 @@ static int addrconf_ifdown(struct net_device *dev, int how) 
	while (!list_empty(&idev->addr_list)) {

		ifa = list_first_entry(&idev->addr_list,

				       struct inet6_ifaddr, if_list);

		addrconf_del_dad_timer(ifa);

		addrconf_del_dad_work(ifa);



		list_del(&ifa->if_list);
@@ -3148,10 +3170,10 @@ static void addrconf_dad_kick(struct inet6_ifaddr *ifp) 
		rand_num = prandom_u32() % (idev->cnf.rtr_solicit_delay ? : 1);



	ifp->dad_probes = idev->cnf.dad_transmits;

	addrconf_mod_dad_timer(ifp, rand_num);

	addrconf_mod_dad_work(ifp, rand_num);

}



static void addrconf_dad_start(struct inet6_ifaddr *ifp)

static void addrconf_dad_begin(struct inet6_ifaddr *ifp)

{

	struct inet6_dev *idev = ifp->idev;

	struct net_device *dev = idev->dev;
@@ -3203,25 +3225,68 @@ out: 
	read_unlock_bh(&idev->lock);

}



static void addrconf_dad_timer(unsigned long data)

static void addrconf_dad_start(struct inet6_ifaddr *ifp)

{

	struct inet6_ifaddr *ifp = (struct inet6_ifaddr *) data;

	bool begin_dad = false;



	spin_lock_bh(&ifp->state_lock);

	if (ifp->state != INET6_IFADDR_STATE_DEAD) {

		ifp->state = INET6_IFADDR_STATE_PREDAD;

		begin_dad = true;

	}

	spin_unlock_bh(&ifp->state_lock);



	if (begin_dad)

		addrconf_mod_dad_work(ifp, 0);

}



static void addrconf_dad_work(struct work_struct *w)

{

	struct inet6_ifaddr *ifp = container_of(to_delayed_work(w),

						struct inet6_ifaddr,

						dad_work);

	struct inet6_dev *idev = ifp->idev;

	struct in6_addr mcaddr;



	enum {

		DAD_PROCESS,

		DAD_BEGIN,

		DAD_ABORT,

	} action = DAD_PROCESS;



	rtnl_lock();



	spin_lock_bh(&ifp->state_lock);

	if (ifp->state == INET6_IFADDR_STATE_PREDAD) {

		action = DAD_BEGIN;

		ifp->state = INET6_IFADDR_STATE_DAD;

	} else if (ifp->state == INET6_IFADDR_STATE_ERRDAD) {

		action = DAD_ABORT;

		ifp->state = INET6_IFADDR_STATE_POSTDAD;

	}

	spin_unlock_bh(&ifp->state_lock);



	if (action == DAD_BEGIN) {

		addrconf_dad_begin(ifp);

		goto out;

	} else if (action == DAD_ABORT) {

		addrconf_dad_stop(ifp, 1);

		goto out;

	}



	if (!ifp->dad_probes && addrconf_dad_end(ifp))

		goto out;



	write_lock(&idev->lock);

	write_lock_bh(&idev->lock);

	if (idev->dead || !(idev->if_flags & IF_READY)) {

		write_unlock(&idev->lock);

		write_unlock_bh(&idev->lock);

		goto out;

	}



	spin_lock(&ifp->lock);

	if (ifp->state == INET6_IFADDR_STATE_DEAD) {

		spin_unlock(&ifp->lock);

		write_unlock(&idev->lock);

		write_unlock_bh(&idev->lock);

		goto out;

	}
@@ -3232,7 +3297,7 @@ static void addrconf_dad_timer(unsigned long data) 


		ifp->flags &= ~(IFA_F_TENTATIVE|IFA_F_OPTIMISTIC|IFA_F_DADFAILED);

		spin_unlock(&ifp->lock);

		write_unlock(&idev->lock);

		write_unlock_bh(&idev->lock);



		addrconf_dad_completed(ifp);
@@ -3240,16 +3305,17 @@ static void addrconf_dad_timer(unsigned long data) 
	}



	ifp->dad_probes--;

	addrconf_mod_dad_timer(ifp,

	addrconf_mod_dad_work(ifp,

			      NEIGH_VAR(ifp->idev->nd_parms, RETRANS_TIME));

	spin_unlock(&ifp->lock);

	write_unlock(&idev->lock);

	write_unlock_bh(&idev->lock);



	/* send a neighbour solicitation for our addr */

	addrconf_addr_solict_mult(&ifp->addr, &mcaddr);

	ndisc_send_ns(ifp->idev->dev, NULL, &ifp->addr, &mcaddr, &in6addr_any);

out:

	in6_ifa_put(ifp);

	rtnl_unlock();

}



/* ifp->idev must be at least read locked */
@@ -3276,7 +3342,7 @@ static void addrconf_dad_completed(struct inet6_ifaddr *ifp) 
	struct in6_addr lladdr;

	bool send_rs, send_mld;



	addrconf_del_dad_timer(ifp);

	addrconf_del_dad_work(ifp);



	/*

	 *	Configure the address for reception. Now it is valid.
@@ -3517,23 +3583,23 @@ int ipv6_chk_home_addr(struct net *net, const struct in6_addr *addr) 
 *	Periodic address status verification

 */



static void addrconf_verify(unsigned long foo)

static void addrconf_verify_rtnl(void)

{

	unsigned long now, next, next_sec, next_sched;

	struct inet6_ifaddr *ifp;

	int i;



	ASSERT_RTNL();



	rcu_read_lock_bh();

	spin_lock(&addrconf_verify_lock);

	now = jiffies;

	next = round_jiffies_up(now + ADDR_CHECK_FREQUENCY);



	del_timer(&addr_chk_timer);

	cancel_delayed_work(&addr_chk_work);



	for (i = 0; i < IN6_ADDR_HSIZE; i++) {

restart:

		hlist_for_each_entry_rcu_bh(ifp,

					 &inet6_addr_lst[i], addr_lst) {

		hlist_for_each_entry_rcu_bh(ifp, &inet6_addr_lst[i], addr_lst) {

			unsigned long age;



			/* When setting preferred_lft to a value not zero or
@@ -3628,13 +3694,22 @@ restart: 


	ADBG(KERN_DEBUG "now = %lu, schedule = %lu, rounded schedule = %lu => %lu\n",

	      now, next, next_sec, next_sched);



	addr_chk_timer.expires = next_sched;

	add_timer(&addr_chk_timer);

	spin_unlock(&addrconf_verify_lock);

	mod_delayed_work(addrconf_wq, &addr_chk_work, next_sched - now);

	rcu_read_unlock_bh();

}



static void addrconf_verify_work(struct work_struct *w)

{

	rtnl_lock();

	addrconf_verify_rtnl();

	rtnl_unlock();

}



static void addrconf_verify(void)

{

	mod_delayed_work(addrconf_wq, &addr_chk_work, 0);

}



static struct in6_addr *extract_addr(struct nlattr *addr, struct nlattr *local,

				     struct in6_addr **peer_pfx)

{
@@ -3691,6 +3766,8 @@ static int inet6_addr_modify(struct inet6_ifaddr *ifp, u32 ifa_flags, 
	bool was_managetempaddr;

	bool had_prefixroute;



	ASSERT_RTNL();



	if (!valid_lft || (prefered_lft > valid_lft))

		return -EINVAL;
@@ -3756,7 +3833,7 @@ static int inet6_addr_modify(struct inet6_ifaddr *ifp, u32 ifa_flags, 
				 !was_managetempaddr, jiffies);

	}



	addrconf_verify(0);

	addrconf_verify_rtnl();



	return 0;

}
@@ -4386,6 +4463,8 @@ static int inet6_set_iftoken(struct inet6_dev *idev, struct in6_addr *token) 
	bool update_rs = false;

	struct in6_addr ll_addr;



	ASSERT_RTNL();



	if (token == NULL)

		return -EINVAL;

	if (ipv6_addr_any(token))
@@ -4434,7 +4513,7 @@ static int inet6_set_iftoken(struct inet6_dev *idev, struct in6_addr *token) 
	}



	write_unlock_bh(&idev->lock);

	addrconf_verify(0);

	addrconf_verify_rtnl();

	return 0;

}
@@ -4636,6 +4715,9 @@ static void __ipv6_ifa_notify(int event, struct inet6_ifaddr *ifp) 
{

	struct net *net = dev_net(ifp->idev->dev);



	if (event)

		ASSERT_RTNL();



	inet6_ifa_notify(event ? : RTM_NEWADDR, ifp);



	switch (event) {
@@ -5244,6 +5326,12 @@ int __init addrconf_init(void) 
	if (err < 0)

		goto out_addrlabel;



	addrconf_wq = create_workqueue("ipv6_addrconf");

	if (!addrconf_wq) {

		err = -ENOMEM;

		goto out_nowq;

	}



	/* The addrconf netdev notifier requires that loopback_dev

	 * has it's ipv6 private information allocated and setup

	 * before it can bring up and give link-local addresses
@@ -5274,7 +5362,7 @@ int __init addrconf_init(void) 


	register_netdevice_notifier(&ipv6_dev_notf);



	addrconf_verify(0);

	addrconf_verify();



	rtnl_af_register(&inet6_ops);
@@ -5302,6 +5390,8 @@ errout: 
	rtnl_af_unregister(&inet6_ops);

	unregister_netdevice_notifier(&ipv6_dev_notf);

errlo:

	destroy_workqueue(addrconf_wq);

out_nowq:

	unregister_pernet_subsys(&addrconf_ops);

out_addrlabel:

	ipv6_addr_label_cleanup();
@@ -5337,7 +5427,8 @@ void addrconf_cleanup(void) 
	for (i = 0; i < IN6_ADDR_HSIZE; i++)

		WARN_ON(!hlist_empty(&inet6_addr_lst[i]));

	spin_unlock_bh(&addrconf_hash_lock);



	del_timer(&addr_chk_timer);

	cancel_delayed_work(&addr_chk_work);

	rtnl_unlock();



	destroy_workqueue(addrconf_wq);

}