Commit 3cd3e72c authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

inet: annotate data-races around ifa->ifa_tstamp and ifa->ifa_cstamp 



ifa->ifa_tstamp can be read locklessly.

Add appropriate READ_ONCE()/WRITE_ONCE() annotations.

Do the same for ifa->ifa_cstamp to prepare upcoming changes.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 76f06cbd

net/ipv4/devinet.c

+13 −10
Original line number Diff line number Diff line
@@ -713,13 +713,14 @@ static void check_lifetime(struct work_struct *work) 


		rcu_read_lock();

		hlist_for_each_entry_rcu(ifa, &inet_addr_lst[i], hash) {

			unsigned long age;

			unsigned long age, tstamp;



			if (ifa->ifa_flags & IFA_F_PERMANENT)

				continue;



			tstamp = READ_ONCE(ifa->ifa_tstamp);

			/* We try to batch several events at once. */

			age = (now - ifa->ifa_tstamp +

			age = (now - tstamp +

			       ADDRCONF_TIMER_FUZZ_MINUS) / HZ;



			if (ifa->ifa_valid_lft != INFINITY_LIFE_TIME &&
@@ -729,17 +730,17 @@ static void check_lifetime(struct work_struct *work) 
				   INFINITY_LIFE_TIME) {

				continue;

			} else if (age >= ifa->ifa_preferred_lft) {

				if (time_before(ifa->ifa_tstamp +

				if (time_before(tstamp +

						ifa->ifa_valid_lft * HZ, next))

					next = ifa->ifa_tstamp +

					next = tstamp +

					       ifa->ifa_valid_lft * HZ;



				if (!(ifa->ifa_flags & IFA_F_DEPRECATED))

					change_needed = true;

			} else if (time_before(ifa->ifa_tstamp +

			} else if (time_before(tstamp +

					       ifa->ifa_preferred_lft * HZ,

					       next)) {

				next = ifa->ifa_tstamp +

				next = tstamp +

				       ifa->ifa_preferred_lft * HZ;

			}

		}
@@ -819,9 +820,9 @@ static void set_ifa_lifetime(struct in_ifaddr *ifa, __u32 valid_lft, 
			ifa->ifa_flags |= IFA_F_DEPRECATED;

		ifa->ifa_preferred_lft = timeout;

	}

	ifa->ifa_tstamp = jiffies;

	WRITE_ONCE(ifa->ifa_tstamp, jiffies);

	if (!ifa->ifa_cstamp)

		ifa->ifa_cstamp = ifa->ifa_tstamp;

		WRITE_ONCE(ifa->ifa_cstamp, ifa->ifa_tstamp);

}



static struct in_ifaddr *rtm_to_ifaddr(struct net *net, struct nlmsghdr *nlh,
@@ -1676,6 +1677,7 @@ static int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa, 
{

	struct ifaddrmsg *ifm;

	struct nlmsghdr  *nlh;

	unsigned long tstamp;

	u32 preferred, valid;



	nlh = nlmsg_put(skb, args->portid, args->seq, args->event, sizeof(*ifm),
@@ -1694,11 +1696,12 @@ static int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa, 
	    nla_put_s32(skb, IFA_TARGET_NETNSID, args->netnsid))

		goto nla_put_failure;



	tstamp = READ_ONCE(ifa->ifa_tstamp);

	if (!(ifm->ifa_flags & IFA_F_PERMANENT)) {

		preferred = ifa->ifa_preferred_lft;

		valid = ifa->ifa_valid_lft;

		if (preferred != INFINITY_LIFE_TIME) {

			long tval = (jiffies - ifa->ifa_tstamp) / HZ;

			long tval = (jiffies - tstamp) / HZ;



			if (preferred > tval)

				preferred -= tval;
@@ -1728,7 +1731,7 @@ static int inet_fill_ifaddr(struct sk_buff *skb, struct in_ifaddr *ifa, 
	    nla_put_u32(skb, IFA_FLAGS, ifa->ifa_flags) ||

	    (ifa->ifa_rt_priority &&

	     nla_put_u32(skb, IFA_RT_PRIORITY, ifa->ifa_rt_priority)) ||

	    put_cacheinfo(skb, ifa->ifa_cstamp, ifa->ifa_tstamp,

	    put_cacheinfo(skb, READ_ONCE(ifa->ifa_cstamp), tstamp,

			  preferred, valid))

		goto nla_put_failure;