Commit e7135f48 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

ipv6: annotate data-races around cnf.mtu6 



idev->cnf.mtu6 might be read locklessly, add appropriate READ_ONCE()
and WRITE_ONCE() annotations.

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 553ced03

include/net/ip6_route.h

+1 −1
Original line number Diff line number Diff line
@@ -332,7 +332,7 @@ static inline unsigned int ip6_dst_mtu_maybe_forward(const struct dst_entry *dst 
	rcu_read_lock();

	idev = __in6_dev_get(dst->dev);

	if (idev)

		mtu = idev->cnf.mtu6;

		mtu = READ_ONCE(idev->cnf.mtu6);

	rcu_read_unlock();



out:

net/ipv6/addrconf.c

+2 −2
Original line number Diff line number Diff line
@@ -3671,7 +3671,7 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event, 


		if (idev) {

			rt6_mtu_change(dev, dev->mtu);

			idev->cnf.mtu6 = dev->mtu;

			WRITE_ONCE(idev->cnf.mtu6, dev->mtu);

			break;

		}
@@ -3763,7 +3763,7 @@ static int addrconf_notify(struct notifier_block *this, unsigned long event, 
			if (idev->cnf.mtu6 != dev->mtu &&

			    dev->mtu >= IPV6_MIN_MTU) {

				rt6_mtu_change(dev, dev->mtu);

				idev->cnf.mtu6 = dev->mtu;

				WRITE_ONCE(idev->cnf.mtu6, dev->mtu);

			}

			WRITE_ONCE(idev->tstamp, jiffies);

			inet6_ifinfo_notify(RTM_NEWLINK, idev);

net/ipv6/ndisc.c

+2 −2
Original line number Diff line number Diff line
@@ -1578,8 +1578,8 @@ static enum skb_drop_reason ndisc_router_discovery(struct sk_buff *skb) 


		if (mtu < IPV6_MIN_MTU || mtu > skb->dev->mtu) {

			ND_PRINTK(2, warn, "RA: invalid mtu: %d\n", mtu);

		} else if (in6_dev->cnf.mtu6 != mtu) {

			in6_dev->cnf.mtu6 = mtu;

		} else if (READ_ONCE(in6_dev->cnf.mtu6) != mtu) {

			WRITE_ONCE(in6_dev->cnf.mtu6, mtu);

			fib6_metric_set(rt, RTAX_MTU, mtu);

			rt6_mtu_change(skb->dev, mtu);

		}

net/ipv6/route.c

+3 −3
Original line number Diff line number Diff line
@@ -1596,7 +1596,7 @@ static unsigned int fib6_mtu(const struct fib6_result *res) 


		rcu_read_lock();

		idev = __in6_dev_get(dev);

		mtu = idev->cnf.mtu6;

		mtu = READ_ONCE(idev->cnf.mtu6);

		rcu_read_unlock();

	}
@@ -3249,8 +3249,8 @@ u32 ip6_mtu_from_fib6(const struct fib6_result *res, 


		mtu = IPV6_MIN_MTU;

		idev = __in6_dev_get(dev);

		if (idev && idev->cnf.mtu6 > mtu)

			mtu = idev->cnf.mtu6;

		if (idev)

			mtu = max_t(u32, mtu, READ_ONCE(idev->cnf.mtu6));

	}



	mtu = min_t(unsigned int, mtu, IP6_MAX_MTU);