Commit 2d3916f3 authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

ipv6: fix skb drops in igmp6_event_query() and igmp6_event_report() 



While investigating on why a synchronize_net() has been added recently
in ipv6_mc_down(), I found that igmp6_event_query() and igmp6_event_report()
might drop skbs in some cases.

Discussion about removing synchronize_net() from ipv6_mc_down()
will happen in a different thread.

Fixes: f185de28 ("mld: add new workqueues for process mld events")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Taehee Yoo <ap420073@gmail.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20220303173728.937869-1-eric.dumazet@gmail.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent e1bec7fa

include/net/ndisc.h

+2 −2
Original line number Diff line number Diff line
@@ -475,9 +475,9 @@ int igmp6_late_init(void); 
void igmp6_cleanup(void);

void igmp6_late_cleanup(void);



int igmp6_event_query(struct sk_buff *skb);

void igmp6_event_query(struct sk_buff *skb);



int igmp6_event_report(struct sk_buff *skb);

void igmp6_event_report(struct sk_buff *skb);





#ifdef CONFIG_SYSCTL

net/ipv6/mcast.c

+12 −20
Original line number Diff line number Diff line
@@ -1371,27 +1371,23 @@ static void mld_process_v2(struct inet6_dev *idev, struct mld2_query *mld, 
}



/* called with rcu_read_lock() */

int igmp6_event_query(struct sk_buff *skb)

void igmp6_event_query(struct sk_buff *skb)

{

	struct inet6_dev *idev = __in6_dev_get(skb->dev);



	if (!idev)

		return -EINVAL;



	if (idev->dead) {

		kfree_skb(skb);

		return -ENODEV;

	}

	if (!idev || idev->dead)

		goto out;



	spin_lock_bh(&idev->mc_query_lock);

	if (skb_queue_len(&idev->mc_query_queue) < MLD_MAX_SKBS) {

		__skb_queue_tail(&idev->mc_query_queue, skb);

		if (!mod_delayed_work(mld_wq, &idev->mc_query_work, 0))

			in6_dev_hold(idev);

		skb = NULL;

	}

	spin_unlock_bh(&idev->mc_query_lock);



	return 0;

out:

	kfree_skb(skb);

}



static void __mld_query_work(struct sk_buff *skb)
@@ -1542,27 +1538,23 @@ static void mld_query_work(struct work_struct *work) 
}



/* called with rcu_read_lock() */

int igmp6_event_report(struct sk_buff *skb)

void igmp6_event_report(struct sk_buff *skb)

{

	struct inet6_dev *idev = __in6_dev_get(skb->dev);



	if (!idev)

		return -EINVAL;



	if (idev->dead) {

		kfree_skb(skb);

		return -ENODEV;

	}

	if (!idev || idev->dead)

		goto out;



	spin_lock_bh(&idev->mc_report_lock);

	if (skb_queue_len(&idev->mc_report_queue) < MLD_MAX_SKBS) {

		__skb_queue_tail(&idev->mc_report_queue, skb);

		if (!mod_delayed_work(mld_wq, &idev->mc_report_work, 0))

			in6_dev_hold(idev);

		skb = NULL;

	}

	spin_unlock_bh(&idev->mc_report_lock);



	return 0;

out:

	kfree_skb(skb);

}



static void __mld_report_work(struct sk_buff *skb)