Commit d289ab65 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ipv6: annotate data-races around cnf.disable_ipv6 



disable_ipv6 is read locklessly, add appropriate READ_ONCE()
and WRITE_ONCE() annotations.

v2: do not preload net before rtnl_trylock() in
    addrconf_disable_ipv6() (Jiri)

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarJiri Pirko <jiri@nvidia.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 096361b1

net/ipv6/addrconf.c

+5 −4
Original line number Diff line number Diff line
@@ -4214,7 +4214,7 @@ static void addrconf_dad_work(struct work_struct *w) 
			if (!ipv6_generate_eui64(addr.s6_addr + 8, idev->dev) &&

			    ipv6_addr_equal(&ifp->addr, &addr)) {

				/* DAD failed for link-local based on MAC */

				idev->cnf.disable_ipv6 = 1;

				WRITE_ONCE(idev->cnf.disable_ipv6, 1);



				pr_info("%s: IPv6 being disabled!\n",

					ifp->idev->dev->name);
@@ -6389,7 +6389,8 @@ static void addrconf_disable_change(struct net *net, __s32 newf) 
		idev = __in6_dev_get(dev);

		if (idev) {

			int changed = (!idev->cnf.disable_ipv6) ^ (!newf);

			idev->cnf.disable_ipv6 = newf;



			WRITE_ONCE(idev->cnf.disable_ipv6, newf);

			if (changed)

				dev_disable_change(idev);

		}
@@ -6406,7 +6407,7 @@ static int addrconf_disable_ipv6(struct ctl_table *table, int *p, int newf) 


	net = (struct net *)table->extra2;

	old = *p;

	*p = newf;

	WRITE_ONCE(*p, newf);



	if (p == &net->ipv6.devconf_dflt->disable_ipv6) {

		rtnl_unlock();
@@ -6414,7 +6415,7 @@ static int addrconf_disable_ipv6(struct ctl_table *table, int *p, int newf) 
	}



	if (p == &net->ipv6.devconf_all->disable_ipv6) {

		net->ipv6.devconf_dflt->disable_ipv6 = newf;

		WRITE_ONCE(net->ipv6.devconf_dflt->disable_ipv6, newf);

		addrconf_disable_change(net, newf);

	} else if ((!newf) ^ (!old))

		dev_disable_change((struct inet6_dev *)table->extra1);

net/ipv6/ip6_input.c

+2 −2
Original line number Diff line number Diff line
@@ -168,9 +168,9 @@ static struct sk_buff *ip6_rcv_core(struct sk_buff *skb, struct net_device *dev, 


	SKB_DR_SET(reason, NOT_SPECIFIED);

	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL ||

	    !idev || unlikely(idev->cnf.disable_ipv6)) {

	    !idev || unlikely(READ_ONCE(idev->cnf.disable_ipv6))) {

		__IP6_INC_STATS(net, idev, IPSTATS_MIB_INDISCARDS);

		if (idev && unlikely(idev->cnf.disable_ipv6))

		if (idev && unlikely(READ_ONCE(idev->cnf.disable_ipv6)))

			SKB_DR_SET(reason, IPV6DISABLED);

		goto drop;

	}

net/ipv6/ip6_output.c

+1 −1
Original line number Diff line number Diff line
@@ -234,7 +234,7 @@ int ip6_output(struct net *net, struct sock *sk, struct sk_buff *skb) 
	skb->protocol = htons(ETH_P_IPV6);

	skb->dev = dev;



	if (unlikely(idev->cnf.disable_ipv6)) {

	if (unlikely(READ_ONCE(idev->cnf.disable_ipv6))) {

		IP6_INC_STATS(net, idev, IPSTATS_MIB_OUTDISCARDS);

		kfree_skb_reason(skb, SKB_DROP_REASON_IPV6DISABLED);

		return 0;