Commit 36229b2c authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

net: dst: annotate data-races around dst->expires 



(dst_entry)->expires is read and written locklessly,
add corresponding annotations.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250630121934.3399505-3-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 8a402bbe

include/net/dst.h

+5 −3
Original line number Diff line number Diff line
@@ -431,13 +431,15 @@ static inline void dst_link_failure(struct sk_buff *skb) 


static inline void dst_set_expires(struct dst_entry *dst, int timeout)

{

	unsigned long expires = jiffies + timeout;

	unsigned long old, expires = jiffies + timeout;



	if (expires == 0)

		expires = 1;



	if (dst->expires == 0 || time_before(expires, dst->expires))

		dst->expires = expires;

	old = READ_ONCE(dst->expires);



	if (!old || time_before(expires, old))

		WRITE_ONCE(dst->expires, expires);

}



static inline unsigned int dst_dev_overhead(struct dst_entry *dst,

include/net/ip.h

+1 −1
Original line number Diff line number Diff line
@@ -477,7 +477,7 @@ static inline unsigned int ip_dst_mtu_maybe_forward(const struct dst_entry *dst, 
	    ip_mtu_locked(dst) ||

	    !forwarding) {

		mtu = rt->rt_pmtu;

		if (mtu && time_before(jiffies, rt->dst.expires))

		if (mtu && time_before(jiffies, READ_ONCE(rt->dst.expires)))

			goto out;

	}

net/ipv4/route.c

+4 −3
Original line number Diff line number Diff line
@@ -844,7 +844,7 @@ static void ipv4_negative_advice(struct sock *sk, 


	if ((READ_ONCE(dst->obsolete) > 0) ||

	    (rt->rt_flags & RTCF_REDIRECTED) ||

	    rt->dst.expires)

	    READ_ONCE(rt->dst.expires))

		sk_dst_reset(sk);

}
@@ -1033,7 +1033,8 @@ static void __ip_rt_update_pmtu(struct rtable *rt, struct flowi4 *fl4, u32 mtu) 
	}



	if (rt->rt_pmtu == mtu && !lock &&

	    time_before(jiffies, dst->expires - net->ipv4.ip_rt_mtu_expires / 2))

	    time_before(jiffies, READ_ONCE(dst->expires) -

				 net->ipv4.ip_rt_mtu_expires / 2))

		goto out;



	if (fib_lookup(net, fl4, &res, 0) == 0) {
@@ -3010,7 +3011,7 @@ static int rt_fill_info(struct net *net, __be32 dst, __be32 src, 
		}

	}



	expires = rt->dst.expires;

	expires = READ_ONCE(rt->dst.expires);

	if (expires) {

		unsigned long now = jiffies;

net/ipv6/route.c

+6 −7
Original line number Diff line number Diff line
@@ -391,8 +391,7 @@ static void ip6_dst_ifdown(struct dst_entry *dst, struct net_device *dev) 
static bool __rt6_check_expired(const struct rt6_info *rt)

{

	if (rt->rt6i_flags & RTF_EXPIRES)

		return time_after(jiffies, rt->dst.expires);

	else

		return time_after(jiffies, READ_ONCE(rt->dst.expires));

	return false;

}
@@ -403,7 +402,7 @@ static bool rt6_check_expired(const struct rt6_info *rt) 
	from = rcu_dereference(rt->from);



	if (rt->rt6i_flags & RTF_EXPIRES) {

		if (time_after(jiffies, rt->dst.expires))

		if (time_after(jiffies, READ_ONCE(rt->dst.expires)))

			return true;

	} else if (from) {

		return READ_ONCE(rt->dst.obsolete) != DST_OBSOLETE_FORCE_CHK ||
@@ -2139,7 +2138,7 @@ static void rt6_age_examine_exception(struct rt6_exception_bucket *bucket, 
			rt6_remove_exception(bucket, rt6_ex);

			return;

		}

	} else if (time_after(jiffies, rt->dst.expires)) {

	} else if (time_after(jiffies, READ_ONCE(rt->dst.expires))) {

		pr_debug("purging expired route %p\n", rt);

		rt6_remove_exception(bucket, rt6_ex);

		return;
@@ -2870,7 +2869,7 @@ static void rt6_update_expires(struct rt6_info *rt0, int timeout) 
		rcu_read_lock();

		from = rcu_dereference(rt0->from);

		if (from)

			rt0->dst.expires = from->expires;

			WRITE_ONCE(rt0->dst.expires, from->expires);

		rcu_read_unlock();

	}
@@ -5903,7 +5902,7 @@ static int rt6_fill_node(struct net *net, struct sk_buff *skb, 
	}



	if (rt6_flags & RTF_EXPIRES) {

		expires = dst ? dst->expires : rt->expires;

		expires = dst ? READ_ONCE(dst->expires) : rt->expires;

		expires -= jiffies;

	}